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Title:
AMICA: the NIR/MIR camera for automatic astronomical observations from Dome C, Antarctica

Authors:
Dolci, M.; Straniero, O.; di Rico, G.; Valentini, G.; Riva, A.; di Cianno, A.; Ragni, M.; Giuliani, C.; Valentini, A.; Bortoletto, F.; D'Alessandro, M.; Magrin, D.; Bonoli, C.; Fantinel, D.; Corcione, L.; Abia, C. A.; Busso, M.; Tosti, G.

Affiliation:
AA(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AB(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AC(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AD(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AE(INAF, Osservatorio Astronomico di Torino (Italy)), AF(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AG(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AH(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AI(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AJ(INAF, Osservatorio Astronomico di Padova (Italy)), AK(INAF, Osservatorio Astronomico di Padova (Italy)), AL(INAF, Osservatorio Astronomico di Padova (Italy)), AM(INAF, Osservatorio Astronomico di Padova (Italy)), AN(INAF, Osservatorio Astronomico di Padova (Italy)), AO(INAF, Osservatorio Astronomico di Torino (Italy)), AP(Univ. de Granada (Spain)), AQ(Univ. degli Studi di Perugia (Italy)), AR(Univ. degli Studi di Perugia (Italy))

Publication:
Ground-based and Airborne Instrumentation for Astronomy III. Edited by McLean, Ian S.; Ramsay, Suzanne K.; Takami, Hideki. Proceedings of the SPIE, Volume 7735, pp. 77353L-77353L-12 (2010). (SPIE Homepage)

Publication Date:
07/2010

Origin:
AIP

Abstract Copyright:
(c) 2010: American Institute of Physics

DOI:
10.1117/12.857192

Bibliographic Code:
2010SPIE.7735E.121D

Abstract

AMICA is a double-armed camera designed to perform NIR/ MIR (2-28 μm) Astronomy from Antarctica. It will be installed at Dome C in 2010-2011. An overview of the instrument is given, with attention to the following features: 1) Winterization: AMICA has been tested under Antarctic conditions to be operated in severe environments; 2) Automation: AMICA does not require human intervention; 3) Fast acquisition: AMICA can get images with exposure times less than 3 msec; 4) Survey-mode observations: the low background in Antarctica allows AMICA to have FOVs of 2.29 arcmin (NIR) and 2.89 arcmin (MIR), without saturation even with wide-band filters.

Title:		On the Need for Deep-mixing in Asymptotic Giant Branch Stars of Low Mass
Authors:		Busso, M.; Palmerini, S.; Maiorca, E.; Cristallo, S.; Straniero, O.; Abia, C.; Gallino, R.; La Cognata, M.
Affiliation:		AA(Dipartimento di Fisica, Università di Perugia, Italy ; INFN, Sezione di Perugia, Italy ; ), AB(Dipartimento di Fisica, Università di Perugia, Italy ; INFN, Sezione di Perugia, Italy ), AC(Dipartimento di Fisica, Università di Perugia, Italy ; INFN, Sezione di Perugia, Italy ), AD(Departamento de Física Teórica y del Cosmos, Universidad de Granada, Spain ; INAF, Osservatorio di Teramo, Italy ), AE(INAF, Osservatorio di Teramo, Italy ; INFN, Sezione di Napoli, Italy ), AF(Departamento de Física Teórica y del Cosmos, Universidad de Granada, Spain ), AG(INAF, Osservatorio di Teramo, Italy ; Dipartimento di Fisica Generale, Università di Torino, Italy ), AH(Dipartimento di Metodologie Fisiche e Chimiche per l'Ingegneria, Università di Catania, Italy ; INFN, Laboratori Nazionali del Sud, Catania, Italy)
Publication:		The Astrophysical Journal Letters, Volume 717, Issue 1, pp. L47-L51 (2010). (ApJL Homepage)
Publication Date:		07/2010
Origin:		IOP
ApJ Keywords:		nuclear reactions, nucleosynthesis, abundances, stars: AGB and post-AGB, stars: carbon, stars: evolution, stars: low-mass
DOI:		10.1088/2041-8205/717/1/L47
Bibliographic Code:		2010ApJ...717L..47B

Abstract

The photospheres of low-mass red giants show CNO isotopic abundances that are not satisfactorily accounted for by canonical stellar models. The same is true for the measurements of these isotopes and of the ²⁶Al/²⁷Al ratio in presolar grains of circumstellar origin. Non-convective mixing, occurring during both red giant branch (RGB) and asymptotic giant branch (AGB) stages, is the explanation commonly invoked to account for the above evidence. Recently, the need for such mixing phenomena on the AGB was questioned, and chemical anomalies usually attributed to them were suggested to be formed in earlier phases. We have therefore re-calculated extra-mixing effects in low-mass stars for both the RGB and AGB stages, in order to verify the above claims. Our results contradict them; we actually confirm that slow transport below the convective envelope occurs also on the AGB. This is required primarily by the oxygen isotopic mix and the ²⁶Al content of presolar oxide grains. Other pieces of evidence exist, in particular from the isotopic ratios of carbon stars of type N, or C(N), in the Galaxy and in the LMC, as well as of SiC grains of AGB origin. We further show that, when extra-mixing occurs in the RGB phases of Population I stars above about 1.2 M _sun, this consumes ³He in the envelope, probably preventing the occurrence of thermohaline diffusion on the AGB. Therefore, we argue that other extra-mixing mechanisms should be active in those final evolutionary phases.

Title:		Fluorine Abundances in Galactic Asymptotic Giant Branch Stars
Authors:		Abia, C.; Cunha, K.; Cristallo, S.; de Laverny, P.; Domínguez, I.; Eriksson, K.; Gialanella, L.; Hinkle, K.; Imbriani, G.; Recio-Blanco, A.; Smith, V. V.; Straniero, O.; Wahlin, R.
Affiliation:		AA(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain ), AB(National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726, USA ), AC(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain ), AD(University of Nice-Sophia Antipolis, CNRS (UMR 6202), Cassiopée, Observatoire de la Côte d'Azur, B.P. 4229, 06304 Nice Cedex 4, France ), AE(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain ), AF(Department of Physics & Astronomy, Uppsala University, Box 515, 751 20 Uppsala, Sweden ), AG(INFN Sezione di Napoli, Naples, Italy ), AH(National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726, USA ), AI(Dipt. di Scienze Fisiche, Universitá Federico II, Naples, Italy ), AJ(University of Nice-Sophia Antipolis, CNRS (UMR 6202), Cassiopée, Observatoire de la Côte d'Azur, B.P. 4229, 06304 Nice Cedex 4, France ), AK(National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726, USA ), AL(INAF-Osservatorio di Collurania, 64100 Teramo, Italy), AM(Department of Physics & Astronomy, Uppsala University, Box 515, 751 20 Uppsala, Sweden )
Publication:		The Astrophysical Journal Letters, Volume 715, Issue 2, pp. L94-L98 (2010). (ApJL Homepage)
Publication Date:		06/2010
Origin:		IOP
ApJ Keywords:		nuclear reactions, nucleosynthesis, abundances, stars: abundances, stars: AGB and post-AGB, stars: carbon
DOI:		10.1088/2041-8205/715/2/L94
Bibliographic Code:		2010ApJ...715L..94A

Abstract

An analysis of the fluorine abundance in Galactic asymptotic giant branch (AGB) carbon stars (24 N-type, 5 SC-type, and 5 J-type) is presented. This study uses the state-of-the-art carbon-rich atmosphere models and improved atomic and molecular line lists in the 2.3 μm region. Significantly lower F abundances are obtained in comparison to previous studies in the literature. This difference is mainly due to molecular blends. In the case of carbon stars of SC-type, differences in the model atmospheres are also relevant. The new F enhancements are now in agreement with the most recent theoretical nucleosynthesis models in low-mass AGB stars, solving the long-standing problem of F in Galactic AGB stars. Nevertheless, some SC-type carbon stars still show larger F abundances than predicted by stellar models. The possibility that these stars are of larger mass is briefly discussed.

Title:		Infrared Instrumentation for Dome C: Conceptual Design
Authors:		Mora, Alcione; Eiroa, Carlos; Barrado y Navascués, David; Abia, Carlos; Persi, Paolo
Affiliation:		AA(Departamento de Física Teórica C-XI, Universidad Autónoma de Madrid), AB(Departamento de Física Teórica C-XI, Universidad Autónoma de Madrid), AC(Laboratorio de Astrofísica Espacial y Física Fundamental, INTA), AD(Departamento de Física Teórica y del Cosmos, Universidad de Granada), AE(Istituto di Astrofisica Spaziale e Fisica Cosmica)
Publication:		Highlights of Spanish Astrophysics V, Astrophysics and Space Science Proceedings, Volume . ISBN 978-3-642-11249-2. Springer-Verlag Berlin Heidelberg, 2010, p. 517
Publication Date:		00/2010
Origin:		SPRINGER
DOI:		10.1007/978-3-642-11250-8_155
Bibliographic Code:		2010hsa5.conf..517M

Abstract

We have started a conceptual design study for both a near-infrared (NIR) wide-field camera and a mid-infrared (MIR) camera-spectrograph for a 2m-class telescope at Dome C, Antarctica. The main scientific drivers are the characterization of young embedded objects, the evolution of crystalline silicates in circumstellar disks and the observation of exoplanet secondary transits. Both instrument would exploit the unique features of Dome C: superb seeing, low temperature, improved infrared transmission, reduced sky background and increased atmospheric stability. Two preliminary concepts are presented here. The NIR instrument would cover the wavelength range 0.9-5.5μm and would be optimized for the K, L and M bands. The MIR instrument would observe in the range 7-40μm and would be optimized for the Q window, including the extended portion (25-40μm) only observable from Antarctica.

Title:		Infrared instruments for a 2.5 m telescope at Dome C
Authors:		Mora, A.; Eiroa, C.; Barrado Y Navascués, D.; García-Vargas, M. L.; Maldonado, M.; Sánchez-Blanco, E.; Abia, C.; Persi, P.
Affiliation:		AA(Departamento de Física Teórica, Universidad Autónoma de Madrid, 28049 Madrid, Spain), AB(Departamento de Física Teórica, Universidad Autónoma de Madrid, 28049 Madrid, Spain), AC(Laboratorio de Astrofísica Estelar y Exoplanetas, CAB-INTA, Madrid, Spain), AD(FRACTAL SLNE, Las Rozas de Madrid, Spain), AE(FRACTAL SLNE, Las Rozas de Madrid, Spain), AF(FRACTAL SLNE, Las Rozas de Madrid, Spain), AG(Departamento de Física Teórica y del Cosmos, Universidad de Granada, Spain), AH(Istituto di Astrofisica Spaziale e Fisica Cosmica, Roma, Italy)
Publication:		EAS Publications Series, Volume 40, 2010, pp.183-186
Publication Date:		00/2010
Origin:		EDP Sciences
DOI:		10.1051/eas/1040025
Bibliographic Code:		2010EAS....40..183M

Abstract

We have carried out a conceptual design study for a near-infrared (NIR) wide-field camera and a mid-infrared (MIR) camera-spectrograph for a 2.5 m telescope at Dome C. The main scientific drivers are the characterisation of young embedded objects, the evolution of crystalline silicates in circumstellar disks and the observation of exoplanet secondary transits. Both instrument exploit the unique features of Dome C: improved infrared transmission, reduced sky background, superb seeing, low temperature, and increased atmospheric stability. The NIR camera covers the wavelength range 0.8-5.5 μm and is optimized for the K_dark and L bands. The MIR instrument is sensitive in the range 7-40 μm with a possible extension to the sub-mm. It is optimized for the Q window, including the Q+ extended portion (25-40 μm) only observable from the Antarctic Plateau.

Title:		status of the amica project: ready for the antarctic adventure
Authors:		Dolci, M.; Straniero, O.; di Rico, G.; Ragni, M.; Valentini, G.; di Cianno, A.; Giuliani, C.; Valentini, A.; Taraschi, V.; Bortoletto, F.; D'Alessandro, M.; Magrin, D.; Bonoli, C.; Fantinel, D.; Corcione, L.; Riva, A.; Abia, C.; Busso, M.; Tosti, G.
Affiliation:		AA(INAF – Osservatorio Astronomico di Collurania Teramo, Italy), AB(INAF – Osservatorio Astronomico di Collurania Teramo, Italy), AC(INAF – Osservatorio Astronomico di Collurania Teramo, Italy), AD(INAF – Osservatorio Astronomico di Collurania Teramo, Italy), AE(INAF – Osservatorio Astronomico di Collurania Teramo, Italy), AF(INAF – Osservatorio Astronomico di Collurania Teramo, Italy), AG(INAF – Osservatorio Astronomico di Collurania Teramo, Italy), AH(INAF – Osservatorio Astronomico di Collurania Teramo, Italy), AI(INAF – Osservatorio Astronomico di Collurania Teramo, Italy), AJ(INAF – Osservatorio Astronomico di Padova, Italy), AK(INAF – Osservatorio Astronomico di Padova, Italy), AL(INAF – Osservatorio Astronomico di Padova, Italy), AM(INAF – Osservatorio Astronomico di Padova, Italy), AN(INAF – Osservatorio Astronomico di Padova, Italy), AO(INAF – Osservatorio Astronomico di Torino, Italy), AP(INAF – Osservatorio Astronomico di Torino, Italy), AQ(Universidad de Granada, Spain), AR(Università degli Studi di Perugia, Italy), AS(Università degli Studi di Perugia, Italy)
Publication:		EAS Publications Series, Volume 40, 2010, pp.171-176
Publication Date:		00/2010
Origin:		EDP Sciences
DOI:		10.1051/eas/1040023
Bibliographic Code:		2010EAS....40..171D

Abstract

The status of the AMICA project is reported. Final tests are currently running at Teramo Observatory before moving the instrument to Antarctica. AMICA is a camera equipped with two array detectors to perform astronomical imaging in the 2-28 μm band. It will be mounted at the IRAIT focal plane. Its very special feature is the antarctic operability. AMICA subsystems have been tested at typical antarctic conditions, in order to adopt technological solutions that ensure the correct operation of AMICA even on the antarctic plateau. Moreover, since human operations are not possible during the antarctic “winter", AMICA has been designed to operate in a completely automatic mode. AMICA is essentially aimed to demonstrate the potential of Antarctica for Infrared Astronomy and should therefore produce significant data, both for astronomy and site-testing. In addition, the experience gained in its technological development will be useful for building future astronomical instruments for extreme environment sites.

Title:		science with the irait telescope: the commissioning phase
Authors:		Busso, M.; Bagaglia, M.; Guandalini, R.; Mancini, A.; Nucciarelli, G.; Piluso, A.; Tosti, G.; Dolci, M.; Straniero, O.; Abia, C.
Affiliation:		AA(Dipartimento di Fisica, Università di Perugia, Italy), AB(Dipartimento di Fisica, Università di Perugia, Italy), AC(Dipartimento di Fisica, Università di Perugia, Italy), AD(Dipartimento di Fisica, Università di Perugia, Italy), AE(Dipartimento di Fisica, Università di Perugia, Italy), AF(Dipartimento di Fisica, Università di Perugia, Italy), AG(Dipartimento di Fisica, Università di Perugia, Italy), AH(INAF – Osservatorio di Collurania-Teramo, Italy), AI(INAF – Osservatorio di Collurania-Teramo, Italy), AJ(Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, Spain)
Publication:		EAS Publications Series, Volume 40, 2010, pp.165-170
Publication Date:		00/2010
Origin:		EDP Sciences
DOI:		10.1051/eas/1040022
Bibliographic Code:		2010EAS....40..165B

Abstract

We briefly outline the plans for scientific activities with the International Robotic Antarctic Infrared Telescope (IRAIT), recently mounted at Dome C. We summarize a few fields where infrared observations with the IRAIT telescope can be effective and we focus on a key project for the Commissioning Phase, namely the determination of the luminosity and of evolutionary parameters for evolved Long-Period Variables (LPVs).

Title:		The chemical composition of carbon stars. The R-type stars
Authors:		Zamora, O.; Abia, C.; Plez, B.; Domínguez, I.; Cristallo, S.
Affiliation:		AA(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain ), AB(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain), AC(GRAAL, Université Montpellier II, CNRS, 34095 Montpellier Cedex 5, France), AD(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain), AE(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain; INAF, Osservatorio Astronomico di Collurania, 64100 Teramo, Italy)
Publication:		Astronomy and Astrophysics, Volume 508, Issue 2, 2009, pp.909-922 (A&A Homepage)
Publication Date:		12/2009
Origin:		EDP Sciences
Keywords:		stars: abundances, stars: chemically peculiar, stars: carbon, stars: AGB and post-AGB
DOI:		10.1051/0004-6361/200912843
Bibliographic Code:		2009A&A...508..909Z

Abstract

Aims. The aim of this work is to shed some light on the problem of the formation of carbon stars of R-type from a detailed study of their chemical composition.
Methods: We use high-resolution and high signal-to-noise optical spectra of 23 R-type stars (both early- and late-types) selected from the Hipparcos catalogue. The chemical analysis is made using spectral synthesis in LTE and state-of-the-art carbon-rich spherical model atmospheres. We derive their CNO content (including the ¹²C/¹³C ratio), average metallicity, lithium, and light (Sr, Y, Zr) and heavy (Ba, La, Nd, Sm) s-element abundances. The observed properties of the stars (galactic distribution, kinematics, binarity, photometry and luminosity) are also discussed.
Results: Our analysis shows that late-R stars are carbon stars with identical chemical and observational characteristics as the normal (N-type) AGB carbon stars. The s-element abundance pattern derived can be reproduced by low-mass AGB nucleosynthesis models where the ¹³C(α, n)¹⁶O reaction is the main neutron donor. We confirm the results of the sole previous abundance analysis of early-R stars, namely that they are carbon stars with near solar metallicity showing enhanced nitrogen, low ¹²C/¹³C ratios and no s-element enhancements. In addition, we have found that early-R stars have Li abundances larger than expected for post RGB tip giants. We also find that a significant number (~40%) of the early-R stars in our sample are wrongly classified, probably being classical CH stars and normal K giants.
Conclusions: On the basis of the chemical analysis, we confirm the previous suggestion that late-R stars are just misclassified N-type carbon stars in the AGB phase of evolution. Their photometric, kinematic, variability and luminosity properties are also compatible with this. In consequence, we suggest that the number of true R stars is considerably lower than previously believed. This alleviates the problem of considering R stars as a frequent stage in the evolution of low-mass stars. We briefly discuss the different scenarios proposed for the formation of early-R stars. The mixing of carbon during an anomalous He-flash is favoured, although no physical mechanism able to trigger that mixing has been found yet. The origin of these stars still remains a mystery.

Title:		Fluorine Abundances in AGB Carbon Stars: New Results?
Authors:		Abia, C.; de Laverny, P.; Recio-Blanco, A.; Domínguez, I.; Cristallo, S.; Straniero, O.
Affiliation:		AA(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain; ), AB(Observatoire de la Côte d'Azur, Dpt. Cassiopée UMR 6202, 06304 Nice Cedex 4, France), AC(Observatoire de la Côte d'Azur, Dpt. Cassiopée UMR 6202, 06304 Nice Cedex 4, France), AD(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain), AE(INAF-Osservatorio di Collurania, 64100 Teramo, Italy), AF(INAF-Osservatorio di Collurania, 64100 Teramo, Italy)
Publication:		Publications of the Astronomical Society of Australia, Volume 26, Issue 3, pp. 351-353. (PASA Homepage)
Publication Date:		09/2009
Origin:		PASA
Keywords:		nuclear reactions, nucleosynthesis, abundances, stars: abundances, stars: AGB, stars: carbon, stars: evolution
DOI:		10.1071/AS08038
Bibliographic Code:		2009PASA...26..351A

Abstract

A recent reanalysis of the fluorine abundance in three Galactic Asymptotic Giant Branch (AGB) carbon stars (TX Psc, AQ Sgr and R Scl) by Abia et al. (2009) results in estimates of fluorine abundances systematically lower by ~0.8 dex on average, with respect to the sole previous estimates by Jorissen, Smith & Lambert (1992). The new F abundances are in better agreement with the predictions of full-network stellar models of low-mass (<3 M_solar) AGB stars.

Title:		Fluorine in Asymptotic Giant Branch Carbon Stars Revisited
Authors:		Abia, C.; Recio-Blanco, A.; de Laverny, P.; Cristallo, S.; Domínguez, I.; Straniero, O.
Affiliation:		AA(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain ), AB(Observatoire de la Côte d'Azur, Department Cassiopée UMR 6202, 06304 Nice Cedex 4, France ), AC(Observatoire de la Côte d'Azur, Department Cassiopée UMR 6202, 06304 Nice Cedex 4, France ), AD(INAF-Osservatorio di Collurania, 64100 Teramo, Italy), AE(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain ), AF(INAF-Osservatorio di Collurania, 64100 Teramo, Italy)
Publication:		The Astrophysical Journal, Volume 694, Issue 2, pp. 971-977 (2009). (ApJ Homepage)
Publication Date:		04/2009
Origin:		IOP
ApJ Keywords:		nuclear reactions, nucleosynthesis, abundances, stars: abundances, stars: AGB and post-AGB, stars: carbon
DOI:		10.1088/0004-637X/694/2/971
Bibliographic Code:		2009ApJ...694..971A

Abstract

A re-analysis of the fluorine abundance in three Galactic asymptotic giant branch (AGB) carbon stars (TX Psc, AQ Sgr, and R Scl) has been performed from the molecular HF (1-0) R9 line at 2.3358 μm. High resolution (R ~ 50,000) and high signal-to-noise spectra obtained with the CRIRES spectrograph and the VLT telescope or from the NOAO archive (for TX Psc) have been used. Our abundance analysis uses the latest generation of MARCS model atmospheres for cool carbon-rich stars. Using spectral synthesis in local thermodynamic equilibrium, we derive for these stars fluorine abundances that are systematically lower by ~0.8 dex in average with respect to the sole previous estimates by Jorissen et al. The possible reasons of this discrepancy are explored. We conclude that the difference may rely on the blending with C-bearing molecules (CN and C₂) that were not properly taken into account in the former study. The new F abundances are in better agreement with the prediction of full network stellar models of low-mass AGB stars. These models also reproduce the s-process elements distribution in the sampled stars. This result, if confirmed in a larger sample of AGB stars, might alleviate the current difficulty to explain the largest [F/O] ratios found by Jorissen et al. In particular, it may not be necessary to search for alternative nuclear chains affecting the production of F in AGB stars.

Title:		Inter-Division IX-X Working Group Encouraging the International Development of Antarctic Astronomy
Authors:		Burton, Michael; Abia, Carlos A.; Carlstrom, John E.; du Foresto, Vincent Coudé; Cui, Xiangqun; Gurovich, Sebastián; Ichikawa, Takashi; Lloyd, James P.; McCaughrean, Mark J.; Tosti, Gino; Zinnecker, Hans
Publication:		Transactions IAU, Volume 4, Issue 27A, Reports on Astronomy 2006-2009. Edited by Karel van der Hucht. Cambridge: Cambridge University Press, 2009, p. 328-329
Publication Date:		00/2009
Origin:		CUP
DOI:		10.1017/S1743921308025799
Bibliographic Code:		2009IAUTA..27..328B

Abstract

Two major astronomical experiments are underway at the US Amundsen-Scott South Pole Station. The first is the South Pole Telescope, a 10m sub-millimetre telescope designed to measure primary and secondary anisotropies in the CMBR, with the aim of placing constraints on the equation of state for dark energy. The second is the IceCube neutrino observatory, which will be a cubic kilometre array designed to image sources of high energy neutrinos.

Title:		Spectroscopy of Carbon Stars in the Draco and Ursa Minor Dwarf Spheroidal Galaxies
Authors:		Abia, C.
Publication:		The Astronomical Journal, Volume 136, Issue 1, pp. 250-258 (2008). (AJ Homepage)
Publication Date:		07/2008
Origin:		IOP
AJ Keywords:		galaxies: dwarf, galaxies: individual: Draco Ursa Minor, stars: abundances, stars: carbon
DOI:		10.1088/0004-6256/136/1/250
Bibliographic Code:		2008AJ....136..250A

Abstract

With the ISIS spectrograph on the William Herschel Telescope, we obtained intermediate-resolution optical spectra in three and five carbon stars belonging to the dwarf spheroidal (dSph) galaxies Draco and Ursa Minor, respectively. The metallicity, carbon isotopic ratios, and high-mass s-element abundances were determined by spectral synthesis in LTE using appropriate spherically symmetric, carbon-rich atmosphere models. The infrared colors and derived luminosities suggest that these stars are equivalent to the classical CH-type stars found in the halo of the Milky Way, although the evidence of luminosity variations in the stars Draco 461 and Draco 20733 may be compatible with these being carbon-rich low-mass asymptotic giant branch stars. The derived overall metallicity in the stellar sample ([M/H] ~-2.0) agrees with the average metallicity of the main stellar component in these dSphs obtained by previous studies. The C/O and ¹²C/¹³C ratios, and the average large heavy-element (Ba, La, Nd, Sm) enhancements derived ([hs/M] >=1) are also similar to the values found in galactic CH-type stars at the same stellar metallicity. Although this average excess in heavy elements can be explained by standard s-process nucleosynthesis models, in two stars of Ursa Minor there is a suggestion that their heavy-element abundance pattern bears a closer resemblance to the scaled solar system r-process than the s-process abundance curve. If this is confirmed, these stars would represent an extragalactic example of the s + r carbon-rich (binary) stars found in the galactic halo. This r-process like abundance pattern has been found previously in other red giant stars belonging to Ursa Minor, suggesting a peculiar chemical evolution history in this dSph galaxy.

Title:		Analysis of Two Carbon Stars in the Carina Dwarf Spheroidal Galaxy
Authors:		Abia, C.; de Laverny, P.; Wahlin, R.; Domínguez, I.; Cristallo, S.; Straniero, O.
Affiliation:		AA(Dpto. Física Teórica y del Cosmos. Universidad de Granada, E-18071 Granada, Spain), AB(Observatoire de la Côte d'Azur, Dpt. Cassiopée UMR6202, 06304 Nice Cedex 4, France), AC(Department of Astronomy and Space Physics, Box 515, 75120 Uppsala, Sweden), AD(Dpto. Física Teórica y del Cosmos. Universidad de Granada, E-18071 Granada, Spain), AE(Osservatorio di Collurania-INAF, Teramo, Italy), AF(Osservatorio di Collurania-INAF, Teramo, Italy)
Publication:		IXTH TORINO WORKSHOP ON EVOLUTION AND NUCLEOSYNTHESIS IN AGB STARS AND THE IIND PERUGIA WORKSHOP ON NUCLEAR ASTROPHYSICS. AIP Conference Proceedings, Volume 1001, pp. 205-212 (2008). (AIPC Homepage)
Publication Date:		04/2008
Origin:		AIP
PACS Keywords:		Carbon stars, S stars, and related types, Population II stars, Stellar structure, interiors, evolution, nucleosynthesis, ages, Abundances, chemical composition, Dwarf galaxies, Spectroscopy and spectrophotometry
DOI:		10.1063/1.2916965
Bibliographic Code:		2008AIPC.1001..205A

Abstract

We present a chemical analysis of two metal-poor carbon stars belonging to the Carina Dwarf Spheroidal galaxy using high resolution optical spectra obtained with the VLT/UVES instrument. Their derived properties and chemical composition are compatible with these stars being in the TP-AGB phase undergoing third dredge-up episodes, although their extrinsic nature cannot be definitively discarded. The analysis indicates that these stars have large s-element enhancements, which are compatible with theoretical s-process nucleosynthesis predictions in low-mass AGB stars (~1.5M_solar), and also large carbon enhancements (C/O>=5), much larger than the values typically found in galactic AGB carbon stars (C/O~1-2). This is also in agreement with the theoretical prediction that carbon stars are formed more easily through third dredge-up episodes as the initial stellar metallicity drops. We speculate on the possibility that the abundance pattern found in the low-mass s-elements (Y, Zr) may be revealing the existence of some chemical depletion into dust grains.

Title:		Chemical analysis of carbon stars in the Local Group. II. The Carina dwarf spheroidal galaxy
Authors:		Abia, C.; de Laverny, P.; Wahlin, R.
Affiliation:		AA(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18 071 Granada, Spain ), AB(Observatoire de la Côte d'Azur, Dpt. Cassiopée UMR6 202, 06 304 Nice Cedex 4, France), AC(Department of Astronomy and Space Physics, Box 515, 75120 Uppsala, Sweden)
Publication:		Astronomy and Astrophysics, Volume 481, Issue 1, 2008, pp.161-168 (A&A Homepage)
Publication Date:		04/2008
Origin:		EDP Sciences
Keywords:		stars: abundances, stars: carbon, galaxies: dwarf, stars: AGB and post-AGB, galaxies: Local Group
DOI:		10.1051/0004-6361:20079114
Bibliographic Code:		2008A&A...481..161A

Abstract

Aims:We present new results of our ongoing chemical study of carbon stars in Local Group galaxies to test the critical dependence of s-process nucleosynthesis on the stellar metallicity.
Methods: We collected optical spectra with the VLT/UVES instrument of two carbon stars found in the Carina Dwarf Spheroidal (dSph) galaxy, namely ALW-C6 and ALW-C7. We performed a full chemical analysis using the new generation of hydrostatic, spherically symmetric carbon-rich model atmospheres and the spectral synthesis method in LTE.
Results: The luminosities, atmosphere parameters and chemical composition of ALW-C6 and ALW-C7 are compatible with these stars being in the TP-AGB phase undergoing third dredge-up episodes, although their extrinsic nature (external pollution in a binary stellar system) cannot be definitively excluded. Our chemical analysis shows that the metallicity of both stars agree with the average metallicity ([Fe/H] -1.8 dex) previously derived for this satellite galaxy from the analysis of both low resolution spectra of RGB stars and the observed colour magnitude diagrams. ALW-C6 and ALW-C7 present strong s-element enhancements, [ s/Fe] = +1.6, +1.5, respectively. These enhancements and the derived s-process indexes [ ls/Fe] , [ hs/Fe] and [ hs/ls] are compatible with theoretical s-process nucleosynthesis predictions in low mass AGB stars ( 1.5 M_ȯ) on the basis that the ¹³C(α,n)¹⁶O is the main source of neutrons. Furthermore, the analysis of C2 and CN bands reveals a large carbon enhancement (C/O 7 and 5, respectively), much larger than the values typically found in galactic AGB carbon stars (C/O 1{-}2). This is also in agreement with the theoretical prediction that AGB carbon stars are formed more easily through third dredge-up episodes as the initial stellar metallicity drops. However, theoretical low-mass AGB models apparently fail to simultaneously fit the observed s-element and carbon enhancements. On the other hand, Zr is found to be less enhanced in ALW-C7 compared to the other elements belonging to the same s-peak. Although the abundance errors are large, the fact that in this star the abundance of Ti (which has a similar condensation temperature to Zr) seems also to be lower than those of others metals, may indicate the existence of some depletion into dust-grains in its photosphere.

Based on

observations collected with the VLT/UT2 telescope (Paranal

Observatory, ESO, Chile) using the UVES (program ID 74.D-0539)

instrument.

Title:		Infrared wide field camera-spectrographs for a 2m-class telescope at Dome C
Authors:		Mora, A.; Eiroa, C.; Barrado Y Navascués, D.; Persi, P.; Abia, C.
Affiliation:		AA(Departamento de Física Teórica C-XI, Universidad Autónoma de Madrid, 28049 Madrid, Spain), AB(Departamento de Física Teórica C-XI, Universidad Autónoma de Madrid, 28049 Madrid, Spain), AC(Laboratorio de Astrofísica Espacial y Física Fundamental, INTA, Madrid, Spain), AD(Istituto di Astrofisica Spaziale e Fisica Cosmica, Roma, Italy), AE(Departamento de Física Teórica y del Cosmos, Universidad de Granada, Spain)
Publication:		EAS Publications Series, Volume 33, 2008, pp.289-292
Publication Date:		00/2008
Origin:		EDP Sciences
DOI:		10.1051/eas:0833042
Bibliographic Code:		2008EAS....33..289M

Abstract

We are exploring instrumental concepts of Near and Mid InfraRed (NIR, MIR) wide field camera-spectrographs for a 2 m-class telescope at Antarctica. Scientific drivers are star formation and very low mass objects. Both concepts pretend to exploit the unique features of Dome C: superb seeing, low temperature, improved IR transmission and reduced sky background. Two preliminary concepts are presented here. The NIR instrument would cover the wavelength range 0.97 5.0 μm and would be optimized for the K, L and M bands. The MIR instrument would observe in the range 7 30 μm and would be specifically designed to exploit the extended portion of the Q window (20+ μm).

Title:		Infrared Observations of Supernovae with IRAIT at Dome C
Authors:		Abia, C.; Domínguez, I.; Dolci, M.; Straniero, O.; Isern, J.; Colomé, J.; Busso, M.; Tosti, G.
Affiliation:		AA(Dpto. Física Teórica y del Cosmos, Universidad de Granada, Spain), AB(Dpto. Física Teórica y del Cosmos, Universidad de Granada, Spain), AC(INAF–Osservatorio Astronomico di Collurania, Teramo, Italy), AD(INAF–Osservatorio Astronomico di Collurania, Teramo, Italy), AE(Institut d'Estudis Espacials de Catalunya (CSIC), Barcelona, Spain), AF(Institut d'Estudis Espacials de Catalunya (CSIC), Barcelona, Spain), AG(Dipartimento di Fisica, Universitá di Perugia, Perugia, Italy), AH(Dipartimento di Fisica, Universitá di Perugia, Perugia, Italy)
Publication:		EAS Publications Series, Volume 33, 2008, pp.239-242
Publication Date:		00/2008
Origin:		EDP Sciences
DOI:		10.1051/eas:0833031
Bibliographic Code:		2008EAS....33..239A

Abstract

Core collapse and thermonuclear supernovae are among the brightest objects in the Universe. However, although we have an ample knowledge of their optical properties, comparatively little is still known in the infrared. Dome C seems to be the best place on Earth for astronomical observations at infrared and submillimeter wavelengths. The telescope IRAIT (International Robotic Antarctic Infrared Telescope) will be the first European astronomical facility at Dome C, and it is planned to be fully operational by the end of 2008. IRAIT will be equipped with the AMICA camera for near- and mid- infrared imaging and photometry. As a key scientific project with IRAIT, we propose a long term study of near- (K) and mid- (LMNQ) infrared light curves of bright supernovae.

Title:		The Chemical Composition of R Stars
Authors:		Zamora, O.; Abia, C.; Dominguez, I.; Plez, B.
Publication:		Why Galaxies Care About AGB Stars: Their Importance as Actors and Probes. ASP Conference Series, Vol. 378, proceedings of the conference held 7-11 August 2006 at University Campus, Vienna, Austria. Edited by F. Kerschbaum, C. Charbonnel, and R. F. Wing. San Francisco: Astronomical Society of the Pacific, 2007., p.141
Publication Date:		11/2007
Origin:		ASPC
Bibliographic Code:		2007ASPC..378..141Z

Abstract

We summarize the results of a chemical analysis of a sample of 23 galactic R stars (cool and warm spectral types) with accurate parallaxes measured by Hipparcos.

Title:		Design and construction of the moving optical systems of IRAIT
Authors:		Colomé, Josep; Abia, Carlos; Domínguez, Inma; Isern, Jordi; Tosti, Gino; Busso, Maurizio; Nucciarelli, Giuliano; Roncella, Fabio; Straniero, Oscar; Dolci, Mauro
Affiliation:		AA(Institut d'Estudis Espacials de Catalunya (IEEC), E-08034 Barcelona, Spain ), AB(Dpto.Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada, Spain), AC(Dpto.Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada, Spain), AD(Institut d'Estudis Espacials de Catalunya (IEEC), E-08034 Barcelona, Spain ; Institut de Ciències de l'Espai (CSIC), E-08034 Barcelona, Spain), AE(Dipartimento di Fisica, Universitá di Perugia, via A. Pascoli, I-06100 Perugia, Italy), AF(Dipartimento di Fisica, Universitá di Perugia, via A. Pascoli, I-06100 Perugia, Italy), AG(Dipartimento di Fisica, Universitá di Perugia, via A. Pascoli, I-06100 Perugia, Italy), AH(Dipartimento di Fisica, Universitá di Perugia, via A. Pascoli, I-06100 Perugia, Italy), AI(INAF-Osservatorio di Teramo, Via Maggini, I-64100 Teramo, Italy), AJ(INAF-Osservatorio di Teramo, Via Maggini, I-64100 Teramo, Italy)
Publication:		Highlights of Astronomy, Volume 14, p. 702-704
Publication Date:		08/2007
Origin:		CUP
DOI:		10.1017/S1743921307012331
Bibliographic Code:		2007HiA....14..702C

Abstract

The IRAIT (International Robotic Antarctic Infrared Telescope) project (Tosti et al. 2006) is based on a 80 cm aperture telescope to observe in the infrared range. It is due to start operations in spring 2008, several months after installation in Dome C (Antarctica). We describe the contributions made to such project by the Institute for Space Studies of Catalonia (IEEC) and the University of Granada, whose participation has been mainly focused in developing the moving optical system for the secondary (M2) and tertiary (M3) mirrors of the telescope. Moving parts of the optical system provide focusing and chopping capabilities, implemented in M2, and a rotation mechanism, implemented in M3, allow observation in either Nasmyth foci. The work package includes the design and construction of both mirrors, the mechanical supports, the electronics and the control software, all prepared to work at the low temperatures at Antarctica. A Spanish company, NTE, was contracted to carry out the design and manufacture. Tests at low temperature and integration in the telescope were finished during summer 2006, before sending the telescope to Antarctica, scheduled by the end of the same year.

Title:		AMICA the infrared eye at Dome C
Authors:		Riva, Alberto; Dolci, Mauro; Straniero, Oscar; Zerbi, Filippo Maria; Molinari, Emilio; Conconi, Paolo; De Caprio, Vincenzo; Valentini, Gaetano; Di Rico, Gianluca; Ragni, Maurizio; Pelusi, Danilo; Di Varano, Igor; Giuliani, Croce; Di Cianno, Amico; Valentini, Angelo; Bortoletto, Favio; D'Alessandro, Maurizio; Bonoli, Carlotta; Giro, Enrico; Fantinel, Daniela; Magrin, Demetrio; Corcione, Leonardo; Busso, Maurizio; Tosti, Gino; Nucciarelli, Giuliano; Roncella, Fabio; Abia, Carlos; Abia
Affiliation:		AA(INAF Osservatorio Astronomico di Brera – Merate, Merate, Italy), AB(INAF Osservatorio Astronomico Collurania Teramo, Teramo, Italy), AC(INAF Osservatorio Astronomico Collurania Teramo, Teramo, Italy), AD(INAF Osservatorio Astronomico di Brera – Merate, Merate, Italy), AE(INAF Osservatorio Astronomico di Brera – Merate, Merate, Italy), AF(INAF Osservatorio Astronomico di Brera – Merate, Merate, Italy), AG(INAF Osservatorio Astronomico di Brera – Merate, Merate, Italy), AH(INAF Osservatorio Astronomico Collurania Teramo, Teramo, Italy), AI(INAF Osservatorio Astronomico Collurania Teramo, Teramo, Italy), AJ(INAF Osservatorio Astronomico Collurania Teramo, Teramo, Italy), AK(INAF Osservatorio Astronomico Collurania Teramo, Teramo, Italy), AL(INAF Osservatorio Astronomico Collurania Teramo, Teramo, Italy), AM(INAF Osservatorio Astronomico Collurania Teramo, Teramo, Italy), AN(INAF Osservatorio Astronomico Collurania Teramo, Teramo, Italy), AO(INAF Osservatorio Astronomico Collurania Teramo, Teramo, Italy), AP(INAF Osservatorio Astronomico di Padova, Padova, Italy), AQ(INAF Osservatorio Astronomico di Padova, Padova, Italy), AR(INAF Osservatorio Astronomico di Padova, Padova, Italy), AS(INAF Osservatorio Astronomico di Padova, Padova, Italy), AT(INAF Osservatorio Astronomico di Padova, Padova, Italy), AU(INAF Osservatorio Astronomico di Padova, Padova, Italy), AV(INAF Osservatorio Astronomico di Torino, Torino, Italy), AW(University of Perugia, Perugia, Italy), AX(University of Perugia, Perugia, Italy), AY(University of Perugia, Perugia, Italy), AZ(University of Perugia, Perugia, Italy), BA(University of Granada, Granada, Spain), BB()
Publication:		Highlights of Astronomy, Volume 14, p. 700-701
Publication Date:		08/2007
Origin:		CUP
DOI:		10.1017/S174392130701232X
Bibliographic Code:		2007HiA....14..700R

Abstract

Amica (Antarctic Multiband Infrared Camera) is a dual-channel Infrared Imager (2-28μm), that will be located at the Nasmyth focus of the IRAIT telescope at Dome C. Dome C base, on Antarctic plateau offers an unique chance for infrared astronomy. It has several advantages like temperature, pressure and site environment. Temperature, around 60°C (mean) allows a good atmospheric stability (good seeing and good windows transparency) a low atmospheric background and the reduction of instrumental background. Pressure (equivalent of 4000 m a.s.l.), implies low content of water vapors; this means higher transmission, broader and new astronomical windows. The site offers the possibility of very long observations (about 6 months winter night).

Title:		AGB nucleosynthesis in the Large Magellanic Cloud. Detailed abundance analysis of the RV Tauri star MACHO 47.2496.8
Authors:		Reyniers, M.; Abia, C.; van Winckel, H.; Lloyd Evans, T.; Decin, L.; Eriksson, K.; Pollard, K. R.
Affiliation:		AA(Instituut voor Sterrenkunde, Departement Natuurkunde en Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium ), AB(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18 071 Granada, Spain), AC(Instituut voor Sterrenkunde, Departement Natuurkunde en Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium), AD(SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, Scotland, UK), AE(Instituut voor Sterrenkunde, Departement Natuurkunde en Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium), AF(Department of Astronomy and Space Physics, Uppsala University, Box 515, 75120 Uppsala, Sweden), AG(Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch, New Zealand)
Publication:		Astronomy and Astrophysics, Volume 461, Issue 2, January II 2007, pp.641-650 (A&A Homepage)
Publication Date:		01/2007
Origin:		EDP Sciences
Keywords:		stars: AGB and post-AGB, stars: abundances, stars: carbon, stars: individual: MACHO 47.2496.8, Magellanic Clouds
DOI:		10.1051/0004-6361:20065893
Bibliographic Code:		2007A&A...461..641R

Abstract

Context: Abundance analysis of post-AGB objects as probes of AGB nucleosynthesis.
Aims: A detailed photospheric abundance study is performed on the carbon-rich post-AGB candidate MACHO 47.2496.8 in the LMC.
Methods: High-resolution, high signal-to-noise ESO VLT-UVES spectra of MACHO 47.2496.8 are analysed by performing detailed spectrum synthesis modelling using state-of-the-art carbon-rich MARCS atmosphere models.
Results: The spectrum of MACHO 47.2496.8 is not only dominated by bands of carbon bearing molecules, but also by lines of atomic transitions of s-process elements. The metallicity of [Fe/H] = -1.4 is surprisingly low for a field LMC star. The C/O ratio, however difficult to quantify, is greater than 2, and the s-process enrichment is large: the light s-process elements are enhanced by 1.2 dex compared to iron ([ls/Fe] = +1.2), while for the heavy s-process elements an even stronger enrichment is measured: [hs/Fe] = +2.1. The lead abundance is comparable to the [hs/Fe]. With its low intrinsic metallicity and its luminosity at the low end of the carbon star luminosity function, the star represents likely the final stage of a low initial mass star.
Conclusions: .The LMC RV Tauri star MACHO 47.2496.8 is highly carbon and s-process enriched, and is most probable a genuine post-C(N-type) AGB star. This is the first detailed abundance analysis of an extragalactic post-AGB star to date.

Title:		AGB Stars: Nucleosynthesis and Open Problems
Authors:		Domínguez, I.; Abia, C.; Cristallo, S.; de Laverny, P.; Straniero, O.
Publication:		Highlights of Spanish Astrophysics IV, Proceedings of the seventh Scientific Meeting of the Spanish Astronomical Society (SEA) held in Barcelona, Spain, September 12-15, 2006. Edited by F. Figueras, Departament d'Astronomia i Meteorologia, Universitat de Barcelona-IEEC; J.M. Girart,Institute de Ciències de l'Espai, CSIC-IEEC; M. Hernanz, Institute de Ciències de l'Espai, CSIC-IEEC; C. Jordi, Departament d'Astronomia i Meteorologia, Universitat de Barcelona-IEEC. ISBN: 978-1-4020-6000-7 (ebook). Published by Springer, Dordrecht, 2007, p.239
Publication Date:		00/2007
Origin:		ADS
Bibliographic Code:		2007hsa..conf..239D

Abstract

Not Available

Title:		GRB 071021: correction to GCNC 6968.
Authors:		Castro-Tirado, A. J.; de Ugarte Postigo, A.; Jelinek, M.; Gorosabel, J.; Marin Fernandez de Capel, A.; Abia, C.; Perez-Ramirez, D.; Malesani, D.; Guziy, S.; Oreiro, R.
Publication:		GRB Coordinates Network, Circular Service, 6971, 1 (2007)
Publication Date:		00/2007
Origin:		SIMBAD
Bibliographic Code:		2007GCN..6971....1C

Abstract

Not Available

Title:		GRB 071021: optical and NIR observations.
Authors:		Castro-Tirado, A. J.; de Ugarte Postigo, A.; Jelinek, M.; Gorosabel, J.; Marin Fernandez de Capel, A.; Abia, C.; Perez-Ramirez, D.; Malesani, D.; Guziy, S.; Oreiro, R.
Publication:		GRB Coordinates Network, Circular Service, 6968, 1 (2007)
Publication Date:		00/2007
Origin:		SIMBAD
Bibliographic Code:		2007GCN..6968....1C

Abstract

Not Available

Title:		Stellar Abundance Analyses: Constraints on Nucleosynthesis and Chemical Evolution?
Authors:		Abia, C.
Affiliation:		AA(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain)
Publication:		EAS Publications Series, Volume 27, 2007, pp.1-9
Publication Date:		00/2007
Origin:		EDP Sciences
DOI:		10.1051/eas:2007140
Bibliographic Code:		2007EAS....27....1A

Abstract

Recent advances in the determination of stellar abundances and their impact on the study of nucleosynthesis and the chemical evolution of galaxies are discussed. It is argued that detailed interpretation of the abundance patterns among chemical elements found at different metallicities still requires solid spectroscopic data. Despite current improvements in abundance analyses, these are not, however, free from systematic errors which can hide the real history of the chemical evolution. Some examples are discussed.

Title:		Moving Optical Systems of IRAIT: Design and Construction
Authors:		Colomé, J.; Abia, C.; Domínguez, I.; Isern, J.; Tosti, G.; Busso, M.; Nucciarelli, G.; Roncella, F.; Straniero, O.; Dolci, M.; The Irait Collaboration Team
Affiliation:		AA(Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona, Spain; ), AB(Dpto. Física Teórica y del Cosmos, Universidad de Granada, Granada, Spain), AC(Dpto. Física Teórica y del Cosmos, Universidad de Granada, Granada, Spain), AD(Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona, Spain ; Institut de Ciències de l'Espai (CSIC-IEEC), Barcelona, Spain), AE(Dipartimento di Fisica, Universitá di Perugia, Perugia, Italy), AF(Dipartimento di Fisica, Universitá di Perugia, Perugia, Italy), AG(Dipartimento di Fisica, Universitá di Perugia, Perugia, Italy), AH(Dipartimento di Fisica, Universitá di Perugia, Perugia, Italy), AI(INAF – Osservatorio di Teramo, Teramo, Italy), AJ(INAF – Osservatorio di Teramo, Teramo, Italy)
Publication:		EAS Publications Series, Volume 25, 2007, pp.221-224
Publication Date:		00/2007
Origin:		EDP Sciences
DOI:		10.1051/eas:2007098
Bibliographic Code:		2007EAS....25..221C

Abstract

The IRAIT (International Robotic Antarctic Infrared Telescope) project (Tosti et al. , 2006, Proc. 6267-29 V. 2) is based on a 80 cm aperture telescope to observe in the infrared range. It is due to start operations in spring 2008, several months after installation in Dome C (Antarctica). We present the contributions made to such project by the Institute for Space Studies of Catalonia (IEEC) and the University of Granada, whose participation is mainly focused in developing the moving optical system for the secondary (M2) and tertiary (M3) mirrors of the telescope. Moving parts of the optical system provide focusing and chopping capabilities, implemented in M2, and a rotation mechanism, implemented in M3, allow observation in either Nasmyth foci. The work package includes the design and construction of both mirrors, the mechanical supports, the electronics and the control software, all prepared to work at the low temperatures at Antarctica. A Spanish company, NTE, was contracted to carry out the design and manufacture. Tests at low temperature and integration in the telescope have been done during summer 2006.

Title:		AMICA: The First camera for Near- and Mid-Infrared Astronomical Imaging at Dome C
Authors:		Straniero, O.; Dolci, M.; Valentini, A.; Valentini, G.; di Rico, G.; Ragni, M.; Giuliani, C.; di Cianno, A.; di Varano, I.; Corcione, L.; Bortoletto, F.; D'Alessandro, M.; Magrin, D.; Bonoli, C.; Giro, E.; Fantinel, D.; Zerbi, F. M.; Riva, A.; de Caprio, V.; Molinari, E.; Conconi, P.; Busso, M.; Tosti, G.; Abia, C. A.
Affiliation:		AA(INAF - OACTe, via Maggini snc, 64100 Teramo, Italy), AB(INAF - OACTe, via Maggini snc, 64100 Teramo, Italy), AC(INAF - OACTe, via Maggini snc, 64100 Teramo, Italy), AD(INAF - OACTe, via Maggini snc, 64100 Teramo, Italy), AE(INAF - OACTe, via Maggini snc, 64100 Teramo, Italy), AF(INAF - OACTe, via Maggini snc, 64100 Teramo, Italy), AG(INAF - OACTe, via Maggini snc, 64100 Teramo, Italy), AH(INAF - OACTe, via Maggini snc, 64100 Teramo, Italy), AI(INAF - OACTe, via Maggini snc, 64100 Teramo, Italy), AJ(INAF - OATo, via Osservatorio 20, 10025 Pino Torinese, Torino, Italy), AK(INAF - OAPd, Vicolo dell'Osservatorio 5, 35122 Padova, Italy), AL(INAF - OAPd, Vicolo dell'Osservatorio 5, 35122 Padova, Italy), AM(INAF - OAPd, Vicolo dell'Osservatorio 5, 35122 Padova, Italy), AN(INAF - OAPd, Vicolo dell'Osservatorio 5, 35122 Padova, Italy), AO(INAF - OAPd, Vicolo dell'Osservatorio 5, 35122 Padova, Italy), AP(INAF - OAPd, Vicolo dell'Osservatorio 5, 35122 Padova, Italy), AQ(INAF - OAMi, Sede di Merate, via E. Bianchi 46, 23807 Merate, Lecco, Italy), AR(INAF - OAMi, Sede di Merate, via E. Bianchi 46, 23807 Merate, Lecco, Italy), AS(INAF - OAMi, Sede di Merate, via E. Bianchi 46, 23807 Merate, Lecco, Italy), AT(INAF – OAMi, Sede di Merate, via E. Bianchi 46, 23807 Merate, Lecco, Italy), AU(INAF – OAMi, Sede di Merate, via E. Bianchi 46, 23807 Merate, Lecco, Italy), AV(Universitá degli Studi di Perugia, Piazza dell'Universitá 1, 06100 Perugia, Italy), AW(Universitá degli Studi di Perugia, Piazza dell'Universitá 1, 06100 Perugia, Italy), AX(Universidad de Granada, Avda. Fuentenueva s/n, 18071 Granada, Spain)
Publication:		EAS Publications Series, Volume 25, 2007, pp.215-220
Publication Date:		00/2007
Origin:		EDP Sciences
DOI:		10.1051/eas:2007097
Bibliographic Code:		2007EAS....25..215S

Abstract

AMICA (Antarctic Multiband Infrared CAmera) is an instrument designed to perform astronomical imaging in the near- (1{-}5 μm) and mid- (5 27 μm) infrared wavelength regions. Equipped with two detectors, an InSb 256² and a Si:As 128² IBC, cooled at 35 and 7 K respectively, it will be the first instrument to investigate the potential of the Italian-French base Concordia for IR astronomy. The main technical challenge is represented by the extreme conditions of Dome C (T ˜ -90 °C, p ˜640 mbar). An environmental control system ensures the correct start-up, shut-down and housekeeping of the various components of the camera. AMICA will be mounted on the IRAIT telescope and will perform survey-mode observations in the Southern sky. The first task is to provide important site-quality data. Substantial contributions to the solution of fundamental astrophysical quests, such as those related to late phases of stellar evolution and to star formation processes, are also expected.

Title:		AMICA (Antarctic Multiband Infrared CAmera) project
Authors:		Dolci, Mauro; Straniero, Oscar; Valentini, Gaetano; Di Rico, Gianluca; Ragni, Maurizio; Pelusi, Danilo; Di Varano, Igor; Giuliani, Croce; Di Cianno, Amico; Valentini, Angelo; Corcione, Leonardo; Bortoletto, Favio; D'Alessandro, Maurizio; Bonoli, Carlotta; Giro, Enrico; Fantinel, Daniela; Magrin, Demetrio; Zerbi, Filippo M.; Riva, Alberto; Molinari, Emilio; Conconi, Paolo; De Caprio, Vincenzo; Busso, Maurizio; Tosti, Gino; Nucciarelli, Giuliano; Roncella, Fabio; Abia, Carlos
Affiliation:		AA(INAF-OACTe (Italy)), AB(INAF-OACTe (Italy)), AC(INAF-OACTe (Italy)), AD(INAF-OACTe (Italy)), AE(INAF-OACTe (Italy)), AF(INAF-OACTe (Italy)), AG(INAF-OACTe (Italy)), AH(INAF-OACTe (Italy)), AI(INAF-OACTe (Italy)), AJ(INAF-OACTe (Italy)), AK(INAF-OATo (Italy)), AL(INAF-OAPd (Italy)), AM(INAF-OAPd (Italy)), AN(INAF-OAPd (Italy)), AO(INAF-OAPd (Italy)), AP(INAF-OAPd (Italy)), AQ(INAF-OAPd (Italy)), AR(INAF-OAMi (Italy)), AS(INAF-OAMi (Italy)), AT(INAF-OAMi (Italy)), AU(INAF-OAMi (Italy)), AV(INAF-OAMi (Italy)), AW(Univ. of Perugia (Italy)), AX(Univ. of Perugia (Italy)), AY(Univ. of Perugia (Italy)), AZ(Univ. of Perugia (Italy)), BA(Univ. de Granada (Spain))
Publication:		Ground-based and Airborne Telescopes. Edited by Stepp, Larry M.. Proceedings of the SPIE, Volume 6267, pp. 62671I (2006). (SPIE Homepage)
Publication Date:		07/2006
Origin:		SPIE
DOI:		10.1117/12.670795
Bibliographic Code:		2006SPIE.6267E..48D

Abstract

The Antarctic Plateau offers unique opportunities for ground-based Infrared Astronomy. AMICA (Antarctic Multiband Infrared CAmera) is an instrument designed to perform astronomical imaging from Dome-C in the near- (1 - 5 μm) and mid- (5 - 27 μm) infrared wavelength regions. The camera consists of two channels, equipped with a Raytheon InSb 256 array detector and a DRS MF-128 Si:As IBC array detector, cryocooled at 35 and 7 K respectively. Cryogenic devices will move a filter wheel and a sliding mirror, used to feed alternatively the two detectors. Fast control and readout, synchronized with the chopping secondary mirror of the telescope, will be required because of the large background expected at these wavelengths, especially beyond 10 μm. An environmental control system is needed to ensure the correct start-up, shut-down and housekeeping of the camera. The main technical challenge is represented by the extreme environmental conditions of Dome C (T about -90 °C, p around 640 mbar) and the need for a complete automatization of the overall system. AMICA will be mounted at the Nasmyth focus of the 80 cm IRAIT telescope and will perform survey-mode automatic observations of selected regions of the Southern sky. The first goal will be a direct estimate of the observational quality of this new highly promising site for Infrared Astronomy. In addition, IRAIT, equipped with AMICA, is expected to provide a significant improvement in the knowledge of fundamental astrophysical processes, such as the late stages of stellar evolution (especially AGB and post-AGB stars) and the star formation.

Title:		The International Robotic Antarctic Infrared Telescope (IRAIT)
Authors:		Tosti, Gino; Busso, Maurizio; Nucciarelli, Giuliano; Bagaglia, Marco; Roncella, Fabio; Mancini, Alberto; Castellini, Sonia; Mariotti, Mirco; Babucci, Ezio; Chiocci, Gianfranco; Straniero, Oscar; Dolci, Mauro; Valentini, Gaetano; di Varano, Igor; Pelusi, Danilo; Di Rico, Gianluca; Ragni, Maurizio; Abia, Carlos; Domínguez, Inma.; Corcione, Leonardo; Porcu, Francesco; Conconi, Paolo; De Caprio, Vincenzo; Riva, Alverto; Molinari, Emilio; Zerbi, Filippo M.; Bortoletto, Favio; Bonoli, Carlotta; D'Alessandro, Maurizio; Colomé, Josep; Isern, Jordi; Briguglio, Runa; Cacciani, Alessandro; Farnesini, Lucio; Checcucci, Bruno; Strassmeier, Klaus G.
Affiliation:		AA(Univ. di Perugia (Italy)), AB(Univ. di Perugia (Italy)), AC(Univ. di Perugia (Italy)), AD(Univ. di Perugia (Italy)), AE(Univ. di Perugia (Italy)), AF(Univ. di Perugia (Italy)), AG(Univ. di Perugia (Italy)), AH(Univ. di Perugia (Italy)), AI(Univ. di Perugia (Italy)), AJ(Univ. di Perugia (Italy)), AK(INAF - Osservatorio di Teramo (Italy)), AL(INAF - Osservatorio di Teramo (Italy)), AM(INAF - Osservatorio di Teramo (Italy)), AN(INAF - Osservatorio di Teramo (Italy)), AO(INAF - Osservatorio di Teramo (Italy)), AP(INAF - Osservatorio di Teramo (Italy)), AQ(INAF - Osservatorio di Teramo (Italy)), AR(Univ. de Granada (Spain)), AS(Univ. de Granada (Spain)), AT(INAF - Osservatorio di Torino (Italy)), AU(INAF - Osservatorio di Torino (Italy)), AV(INAF - Osservatorio Astronomico di Brera (Italy)), AW(INAF - Osservatorio Astronomico di Brera (Italy)), AX(INAF - Osservatorio Astronomico di Brera (Italy)), AY(INAF - Osservatorio Astronomico di Brera (Italy)), AZ(INAF - Osservatorio Astronomico di Brera (Italy)), BA(INAF - Osservatorio Astronomico di Padova (Italy)), BB(INAF - Osservatorio Astronomico di Padova (Italy)), BC(INAF - Osservatorio Astronomico di Padova (Italy)), BD(Institut d'Estudis Espacials de Catalunya (Spain)), BE(Institut d'Estudis Espacials de Catalunya (Spain)), BF(Univ. La Sapienza (Italy)), BG(Univ. La Sapienza (Italy)), BH(INFN - Sezione di Perugia (Italy)), BI(INFN - Sezione di Perugia (Italy)), BJ(Astrophysical Institute Potsdam (Germany))
Publication:		Ground-based and Airborne Telescopes. Edited by Stepp, Larry M.. Proceedings of the SPIE, Volume 6267, pp. 62671H (2006). (SPIE Homepage)
Publication Date:		07/2006
Origin:		SPIE
DOI:		10.1117/12.670302
Bibliographic Code:		2006SPIE.6267E..47T

Abstract

Thanks to exceptional coldness, low sky brightness and low content of water vapour of the above atmosphere Dome C, one of the three highest peaks of the large Antarctic plateau, is likely to be the best site on Earth for thermal infrared observations (2.3-300 μm) as well as for the far infrared range (30 μm-1mm). IRAIT (International Robotic Antarctic Infrared Telescope) will be the first European Infrared telescope operating at Dome C. It will be delivered to Antarctica at the end of 2006, will reach Dome C at the end of 2007 and the first winter-over operation will start in spring 2008. IRAIT will offer a unique opportunity for astronomers to test and verify the astronomical quality of the site and it will be a useful test-instrument for a new generation of Antarctic telescopes and focal plane instrumentations. We give here a general overview of the project and of the logistics and transportation options adopted to facilitate the installation of IRAIT at Dome C. We summarize the results of the electrical, electronics and networking tests and of the sky polarization measurements carried out at Dome C during the 2005-2006 summer-campaign. We also present the 25 cm optical telescope (small-IRAIT project) that will installed at Dome C during the Antarctic summer 2006-2007 and that will start observations during the 2007 Antarctic winter when a member of the IRAIT collaboration will join the Italian-French Dome C winter-over team.

Title:		High resolution optical spectroscopy of IRAS 09425-6040 (=GLMP 260)
Authors:		García-Hernández, D. A.; Abia, C.; Manchado, A.; García-Lario, P.
Affiliation:		AA(ISO Data Centre, European Space Astronomy Centre (ESAC), ESA. Villafranca del Castillo. PO Box - Apdo. 50727, 28080 Madrid, Spain ), AB(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain), AC(Instituto de Astrofísica de Canarias, 38200 La Laguna, Spain ; Consejo Superior de Investigaciones Científicas, Spain), AD(ISO Data Centre, European Space Astronomy Centre (ESAC), ESA. Villafranca del Castillo. PO Box - Apdo. 50727, 28080 Madrid, Spain; Herschel Science Centre, Research and Scientific Support Department of ESA, European Space Astronomy Centre (ESAC), Villafranca del Castillo, PO Box- Apdo. 50727, 28080 Madrid, Spain)
Publication:		Astronomy and Astrophysics, Volume 452, Issue 3, June IV 2006, pp.1049-1052 (A&A Homepage)
Publication Date:		06/2006
Origin:		EDP Sciences
Keywords:		stars: AGB and post-AGB, stars: individual: IRAS 09425-6040, stars: abundances
DOI:		10.1051/0004-6361:20065009
Bibliographic Code:		2006A&A...452.1049G

Abstract

We present high resolution optical spectroscopic observations of IRAS 09425-6040, a peculiar, extremely red, C-rich AGB star showing prominent O-rich dust features in its ISO infrared spectrum attributed to crystalline silicates. Our analysis shows that IRAS 09425-6040 is indeed a C-rich star slightly enriched in lithium ({log (Li/H) + 12} ˜ 0.7) with a low ¹²C/¹³C = 15 ± 6 ratio. We also found some evidence that it may be enriched in s-elements. Combining our results with other observational data taken from the literature we conclude that the star is possibly an intermediate-mass TP-AGB star (M ⪆ 3 M_ȯ) close to the end of its AGB evolution which may have only very recently experienced a radical change in its chemistry, turning into a carbon-rich AGB star.

Title:		Chemical analysis of carbon stars in the Local Group
Authors:		de Laverny, P.; Abia, C.; Domínguez, I.; Plez, B.; Straniero, O.; Wahlin, R.; Eriksson, K.; Jørgensen, U. G.
Affiliation:		AA(Observatoire de la Côte d'Azur, Dpt. Cassiopée UMR6 202, 06 304 Nice Cedex 4, France ), AB(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18 071 Granada, Spain), AC(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18 071 Granada, Spain), AD(GRAAL, UMR5024, Université de Montpellier II, 34 095 Montpellier Cedex 5, France), AE(INAF - Osservatorio di Collurania, 64 100 Teramo, Italy), AF(Department of Astronomy and Space Physics, Box 515, 75120 Uppsala, Sweden), AG(Department of Astronomy and Space Physics, Box 515, 75120 Uppsala, Sweden), AH(Niels Bohr Institute, Astronomical Observatory, Juliane Maries vej 30, 2 100 Copenhagen, Denmark)
Publication:		Astronomy and Astrophysics, Volume 446, Issue 3, February II 2006, pp.1107-1118 (A&A Homepage)
Publication Date:		02/2006
Origin:		EDP Sciences
Keywords:		stars: abundances, stars: carbon, nuclear reactions, nucleosynthesis, abundances, galaxies: Local Group
DOI:		10.1051/0004-6361:20053423
Bibliographic Code:		2006A&A...446.1107D

Abstract

We present the first results of our ongoing chemical study of carbon stars in the Local Group of galaxies. We used spectra obtained with UVES at the 8.2 m Kueyen-VLT telescope and a new grid of spherical model atmospheres for cool carbon-rich stars which include polyatomic opacities, to perform a full chemical analysis of one carbon star, BMB-B 30, in the Small Magellanic Cloud (SMC) and two, IGI95-C1 and IGI95-C3, in the Sagittarius Dwarf Spheroidal (Sgr dSph) galaxy. Our main goal is to test the dependence on the stellar metallicity of the s-process nucleosynthesis and mixing mechanism occurring in AGB stars. For these three stars, we find important s-element enhancements with respect to the mean metallicity ([M/H]), namely [s/M]≈+1.0, similar to the figure found in galactic AGB stars of similar metallicity. The abundance ratios derived between elements belonging to the first and second s-process abundance peaks, corresponding to nuclei with a magic number of neutrons N=50 (88Sr, 89Y, 90Zr) and N=82 (138Ba, 139La, 140Ce, 141Pr), agree remarkably well with the theoretical predictions of low mass (M <3~M_ȯ) metal-poor AGB nucleosynthesis models where the main source of neutrons is the ¹³C(α,n)¹⁶O reaction activated during the long interpulse phase, in a small pocket located within the He-rich intershell. The derived C/O and ¹²C/¹³C ratios are, however, more difficult to reconcile with theoretical expectations. Possible explanations, like the extrinsic origin of the composition of these carbon stars or the operation of a non-standard mixing process during the AGB phase (such as the cool bottom process), are discussed on the basis of the collected observational constraints.

Title:		The chemical composition of R-stars
Authors:		Zamora, O.; Abia, C.; Plez, B.; Domınguez, I.
Affiliation:		AA( Departamento de Física Teórica y del Cosmos, Universidad de Granada, Campus Fuentenueva, E-18071 Granada, Spain; ), AB( Departamento de Física Teórica y del Cosmos, Universidad de Granada, Campus Fuentenueva, E-18071 Granada, Spain), AC(GRAAL, UMR5024, Université de Montpellier II, 34 095 Montpellier Cedex 5, France), AD( Departamento de Física Teórica y del Cosmos, Universidad de Granada, Campus Fuentenueva, E-18071 Granada, Spain)
Publication:		Memorie della Società Astronomica Italiana, v.77, p.973 (2006)
Publication Date:		00/2006
Origin:		MmSAI
Keywords:		Stars: carbon stars, Stars: abundances, Stars: nucleosynthesis
Bibliographic Code:		2006MmSAI..77..973Z

Abstract

The preliminary results of the chemical analysis of a sample of 22 galactic R-stars with measured parallaxes are presented. We have derived the C/O and ¹²C/¹³C ratios, the average metallicity ([M/H]) and the Li abundances. We find that most of the stars have ¹²C/¹³C below ˜ 20 with no significant difference between cool and hot R-stars. The C/O ratio ranges between ˜ 1 to 2. We obtain a clear separation in the Li abundance between hot and cool R stars, with a mean value of log epsilon (Li) = +0.90 and log epsilon (Li) =-0.50, respectively. Cool stars are of near solar metallicity whereas hot stars show a larger spread, -0.5< [Fe/H] < +0.1. Concerning the possibility of s-element enhancements, we obtain [Rb/M] > 0 in seven hot stars and in three of them (R-hot) the analysis of the 5924 {Å} TcI line might be compatible with Tc detection. However, the detection of other s-element enhancements is necessary to elucidate the evolutionary stage of these carbon stars of which origin is still unknown.

Title:		A strongly s-process enriched RV Tauri star in the LMC.
Authors:		Reyniers, M.; Abia, C.; Van Winckel, H.; Lloyd Evans, T.; Decin, L.; Eriksson, K.
Affiliation:		AA( Instituut voor Sterrenkunde, Departement Natuurkunde en Sterrenkunde, K.U.Leuven, Celestijnenlaan 200B, 3001 Leuven, Belgium ), AB(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18 071, Granada, Spain), AC(Instituut voor Sterrenkunde, Departement Natuurkunde en Sterrenkunde, K.U.Leuven, Celestijnenlaan 200B, 3001 Leuven, Belgium), AD(School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, Scotland, UK), AE(Natuurkunde en Sterrenkunde, K.U.Leuven, Celestijnenlaan 200B, 3001 Leuven, Belgium), AF(Department of Astronomy and Space Physics, Box 515, 75120 Uppsala, Sweden)
Publication:		Memorie della Società Astronomica Italiana, v.77, p.949 (2006)
Publication Date:		00/2006
Origin:		MmSAI
Keywords:		Stars: AGB and post-AGB, Stars: abundances, Stars: carbon, Stars: individual: MACHO 47.2496.8, Magellanic Clouds
Bibliographic Code:		2006MmSAI..77..949R

Abstract

A detailed abundance analysis is presented of an intriguing object in the Large Magellanic Cloud that links the class of RV Tauri stars to the post-AGB phase of evolution: MACHO 47.2496.8. The spectrum, taken with VLT-UVES, is dominated by molecular lines of carbon bearing molecules, together with strong transitions of s-process species. Detailed spectral syntheses were made using a state-of-the-art carbon rich MARCS model. A surprisingly low metallicity ([Fe/H] = -1.4), together with strong carbon (C/O>2) and s-process overabundances were found, reaching values of [ls/Fe] = +1.2 for the light s-process elements, and even [hs/Fe] = +2.1 for the heavy ones. The strong s-process enhancements are in agreement with the theoretical expectations at that metallicity. Only the combination of a low lead content and a high [hs/ls] is not easily explained by the current nucleosynthetic models. It is not clear whether this star is intrisically or extrinsically enriched, but several arguments favour an intrisic enrichment, implying the object to be a genuine post carbon (N-type) AGB star. With the low metallicity and a luminosity at the very low end of the carbon star luminosity function, MACHO 47.2496.8 represents the final evolutionary state of a star of low initial mass.

Based on observations collected at ESO, Chile (programme 074.D-0619(A))

Title:		VIII Torino Workshop on Nucleosynthesis in AGB Stars
Authors:		Abia, Carlos; Dominguez, Imma
Publication:		Memorie della Società Astronomica Italiana, v.77, p.765 (2006)
Publication Date:		00/2006
Origin:		MmSAI
Bibliographic Code:		2006MmSAI..77..765A

Abstract

Not Available

Title:		Chemical Analysis of Extragalactic Carbon Stars
Authors:		de Laverny, P.; Abia, C.; Domínguez, I.; Plez, B.; Straniero, O.
Affiliation:		AA(Dpt. Cassiopée, Observatoire de la Côte d’Azur), AB(Universidad da Granada), AC(Universidad da Granada), AD(GRAAL, Université Montpellier II), AE(Osservatorio di Collurania)
Publication:		Chemical Abundances and Mixing in Stars in the Milky Way and its Satellites, ESO ASTROPHYSICS SYMPOSIA. ISBN 978-3-540-34135-2. Springer-Verlag, 2006, p. 262
Publication Date:		00/2006
Origin:		SPRINGER
Bibliographic Code:		2006cams.book..262D

Abstract

We have performed the chemical analysis of extragalactic carbon stars from VLT/UVES spectra. The derived individual abundances of metals and s-elements as well as the well known distance of the selected stars in the Small Magellanic Cloud and the Sagittarius dwarf galaxies permit us to test current models of stellar evolution and nucleosynthesis during the Asymptotic Giant Branch phase in low metallicity environments.

Title:		Observational Constraints on Nucleosynthesis in AGB Stars
Authors:		Abia, C.; Domínguez, I.; Straniero, O.; Zamora, O.
Affiliation:		AA(Dpto. Física Teórica y del Cosmos, Universidad de Granada), AB(Dpto. Física Teórica y del Cosmos, Universidad de Granada), AC(INAF – Osservatorio Astronomico di Collurania), AD(Dpto. Física Teórica y del Cosmos, Universidad de Granada)
Publication:		Chemical Abundances and Mixing in Stars in the Milky Way and its Satellites, ESO ASTROPHYSICS SYMPOSIA. ISBN 978-3-540-34135-2. Springer-Verlag, 2006, p. 23
Publication Date:		00/2006
Origin:		SPRINGER
Bibliographic Code:		2006cams.book...23A

Abstract

AGB stars, in particular those of carbon types, are excellent laboratories to constraint the theory of stellar structure, evolution and nucleosynthesis. Despite the uncertainties still existing in the chemical analysis of these stars, the determination of the abundances of several key species in their atmospheres (lithium, s-elements, carbon and magnesium isotopic ratios etc.) is an useful tool to test these theories and the mixing processes during the AGB phase. This contribution briefly review some recent advances on this subject.

Title:		Abundances of s-elements in Extragalactic Carbon Stars
Authors:		de Laverny, P.; Abia, C.; Domínguez, I.; Plez, B.; Straniero, O.; Wahlin, R.; Eriksson, K.; Jørgensen, U. G.
Publication:		From Lithium to Uranium: Elemental Tracers of Early Cosmic Evolution, IAU Symposium Proceedings of the international Astronomical Union 228, Held in Paris, France, May 23-27, 2005. edited by Hill, V.; François, P.; Primas, F. Cambridge: Cambridge University Press, 2005., pp.533-534
Publication Date:		00/2005
Origin:		CUP
DOI:		10.1017/S1743921305006393
Bibliographic Code:		2005IAUS..228..533D

Abstract

Carbon stars found in the Small Magellanic Cloud and the Sagittarius Dwarf Spheroidal galaxy have been chemically analysed. We found that the abundance ratios derived between elements belonging to the first and the second s-process abundance peaks agree remarkably well with the theoretical predictions of low mass metal-poor AGB nucleosynthesis models. Together with their estimated luminosities, their derived abundances and their carbon isotopic ratio we speculate on the evolutionary status of these carbon stars.

Title:		The IRAIT Project Infrared Astronomy from Antarctica
Authors:		Busso, M.; Tosti, G.; Roncella, F.; Bagaglia, M.; Nucciarelli, G.; Fastellini, R.; Straniero, O.; Dolci, M.; Ragni, M.; di Varano, I.; Corcione, L.; Abia, C.; Dominguez, I.; Rossi, F.; Nicolini, A.
Affiliation:		AA(Department of Physics, University of Perugia, Italy), AB(Department of Physics, University of Perugia, Italy), AC(Department of Physics, University of Perugia, Italy), AD(Department of Physics, University of Perugia, Italy), AE(Department of Physics, University of Perugia, Italy), AF(Department of Physics, University of Perugia, Italy), AG(INAF, Observatory of Collurania - Teramo, Italy), AH(INAF, Observatory of Collurania - Teramo, Italy), AI(INAF, Observatory of Collurania - Teramo, Italy), AJ(INAF, Observatory of Collurania - Teramo, Italy), AK(INAF, Observatory of Torino, Italy), AL(Istituto de Física Teórica y del Cosmo, Universidad de Granada, Spain), AM(Istituto de Física Teórica y del Cosmo, Universidad de Granada, Spain), AN(Department of Industrial Engineering, University of Perugia, Italy), AO(Department of Industrial Engineering, University of Perugia, Italy)
Publication:		EAS Publications Series, Volume 14, 2005, pp.181-186
Publication Date:		00/2005
Origin:		EDP Sciences
DOI:		10.1051/eas:2005028
Bibliographic Code:		2005EAS....14..181B

Abstract

The Concordia Station (Candidi 2003), on the Antarctica Plateau, will soon become one of the best observatories to perform infrared observations in the 2 20 μm atmospheric windows and beyond, thanks to its low sky background, low temperature and high atmospheric transparency. The possibility of passively cooling the telescope is a further advantage. We describe here the first permanent Antarctic infrared telescope, under development for the Dome C base. It is the International Robotic Antarctic Infrared Telescope (IRAIT). We briefly outline a few scientific motivations for it, then we review the technical characteristics and the status of its development. The infrared camera for IRAIT is described in another dedicated paper in this volume.

Title:		The IRAIT Project: infrared astronomy from Antartica
Authors:		Tosti, Gino; Busso, Maurizio; Straniero, Oscar; Abia, Carlos; Bagaglia, Marco; Dolci, Mauro; Corcione, Leonardo; Nucciarelli, Giuliano; Roncella, Fabio; Valentini, Gaetano; Di Varano, Igor; Pelusi, Danilo
Affiliation:		AA(Univ. degli Studi di Perugia (Italy)), AB(Univ. degli Studi di Perugia (Italy)), AC(INAF, Osservatorio Astronomico di Collurania - Teramo (Italy)), AD(Univ. de Granada (Spain)), AE(Univ. degli Studi di Perugia (Italy)), AF(INAF, Osservatorio Astronomico di Collurania - Teramo (Italy)), AG(INAF, Osservatorio Astronomico di Torino (Italy)), AH(Univ. degli Studi di Perugia (Italy)), AI(Univ. degli Studi di Perugia (Italy)), AJ(INAF, Osservatorio Astronomico di Collurania - Teramo (Italy)), AK(INAF, Osservatorio Astronomico di Collurania - Teramo (Italy)), AL(INAF, Osservatorio Astronomico di Collurania - Teramo (Italy))
Publication:		Ground-based Telescopes. Edited by Oschmann, Jacobus M., Jr. Proceedings of the SPIE, Volume 5489, pp. 742-753 (2004). (SPIE Homepage)
Publication Date:		10/2004
Origin:		SPIE
DOI:		10.1117/12.551162
Bibliographic Code:		2004SPIE.5489..742T

Abstract

The Antarctica Plateau has recently turned out to be the best place on the Earth to perform astronomical infrared observations in the 2-20 um atmospheric windows and beyond, thanks to the extremely low sky background emission, the excellent atmospheric transparency and stability, the virtual absence of winds and the possibility of passively cooling the telescope and its focal plane instruments down to very low temperatures. Dome C, a site jointly exploited by Italian and French scientific teams in the framework of the Concordia project, lays on the Antarctica Plateau at an altitude of 3200m and presents exceptionally cold and dry climatic conditions. In this paper we shall describe the scientific motivations and the technical details of the infrared telescope IRAIT that we plan to put at Dome C starting from in 2005-2006. The IRAIT telescope is an alt-azimuth f/20 reflector, with a 0.8m parabolic primary mirror and a wobbling secondary mirror suitable for the specific techniques of IR observations. It will be equipped with a Near/Mid IR-camera built in Italy .

Title:		First detection of a lithium rich carbon star in the Draco dwarf galaxy: Evidence for a young stellar population
Authors:		Domínguez, I.; Abia, C.; Straniero, O.; Cristallo, S.; Pavlenko, Ya. V.
Affiliation:		AA(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain ), AB(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain), AC(INAF-Osservatorio Astronomico di Collurania, 64100 Teramo, Italy), AD(INAF-Osservatorio Astronomico di Collurania, 64100 Teramo, Italy), AE(Main Astronomical Observatory, National Academy of Sciences, Zabolotnoho 27, Kiev-127 03680, Ukranie)
Publication:		Astronomy and Astrophysics, v.422, p.1045-1052 (2004) (A&A Homepage)
Publication Date:		08/2004
Origin:		A&A
A&A Keywords:		stars: carbon, stars: abundances, stars: evolution, stars: AGB and post-AGB, galaxies: local group
DOI:		10.1051/0004-6361:20040289
Bibliographic Code:		2004A&A...422.1045D

Abstract

We present a spectroscopic study of D461, a giant star belonging to Draco dwarf spheroidal galaxy. From spectral synthesis in LTE we derive a lithium abundance of log ɛ(Li) = 3.5±0.4 and a C/O ratio between 3 and 5. This is the first detection of a lithium rich C-star in a dwarf spheroidal galaxy. Basing on stellar models of appropriate chemical composition, we show that a similar C enrichment is compatible with that expected for a low mass low metallicity thermally pulsing AGB star, undergoing few third dredge up episodes. The position in the log g-log T_eff diagram of D461 is also compatible with this theoretical scenario. In particular, the low effective temperature, lower than that expected for a low metallicity giant star, is a consequence of the huge increase of the envelope opacity occurring after the carbon dredge up. The Li enrichment may be explained if a deep circulation would take place during the interpulse period, the so called cool bottom process. In spite of the low resolution of our spectra, we derive a lower limit for the carbon isotopic ratio, namely ¹²C/¹³C>40, and a constraint for the Ba abundance, namely 0.5<[Ba/Fe]< 2. The proposed scenario also fits these further constraints. Then, we estimate that the mass of D461 ranges between 1.2 and 2 M_ȯ, which corresponds to an age ranging between 1 and 3 Gyr. We conclude that this star is more massive and younger than the typical stellar population of Draco.

Title:		Magnesium abundances in mildly metal-poor stars from different indicators
Authors:		Abia, C.; Mashonkina, L.
Affiliation:		AA(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain), AB(Department of Astronomy, Kazan State University, Kremlevskaya 18, 420008 Kazan 8, Russia)
Publication:		Monthly Notices of the Royal Astronomical Society, Volume 350, Issue 3, pp. 1127-1140. (MNRAS Homepage)
Publication Date:		05/2004
Origin:		MNRAS
MNRAS Keywords:		stars: abundances, stars: atmospheres, Galaxy: evolution
DOI:		10.1111/j.1365-2966.2004.07728.x
Bibliographic Code:		2004MNRAS.350.1127A

Abstract

We present Mg abundances derived from high-resolution spectra using several MgI and two high-excitation MgII lines for 19 metal-poor stars with [Fe/H] values between -1.1 and +0.2. The main goal is to search for systematic differences in the derived abundances between the two ionization state lines. Our analysis shows that the one-dimensional local thermodynamic equilibrium (LTE) and non-LTE (N-LTE) study finds a very good agreement between these features. The [Mg/Fe] versus [Fe/H] relationship derived, despite the small sample of stars, is also in agreement with the classical figure of increasing [Mg/Fe] with decreasing metallicity. We find a significant scatter however, in the [Mg/Fe] ratio at [Fe/H]~-0.6 which is currently explained as a consequence of the overlap at this metallicity of thick- and thin-disc stars, which were probably formed from material with different nucleosynthesis histories. We speculate on the possible consequences of the agreement found between MgI and MgII lines on the very well-known O problem in metal-poor stars. We also study the [O/Mg] ratio in the sample stars using O abundances from the literature and find that the current observations and nucleosynthetic predictions from Type II supernovae disagree. We briefly discuss some alternatives to solve this discrepancy.

Title:		s-Processing in AGB Stars and the Composition of Carbon Stars
Authors:		Busso, Maurizio; Straniero, Oscar; Gallino, Roberto; Abia, Carlos
Affiliation:		AA(Dipartimiento di Fisica, Università di Perugia, Perugia, Italy), AB(Osservatorio Astronomico di Collurania, Teramo, Italy), AC(Dipartimento di Fisica Generale, Università di Torino, Torino, Italy), AD(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain)
Publication:		Origin and Evolution of the Elements, from the Carnegie Observatories Centennial Symposia. Published by Cambridge University Press, as part of the Carnegie Observatories Astrophysics Series. Edited by A. McWilliam and M. Rauch, 2004, p. 67.
Publication Date:		00/2004
Origin:		AUTHOR
Bibliographic Code:		2004oee..symp...67B

Abstract

We briefly review the researches on s-process nucleosynthesis, starting from the original studies where the phenomenological approach based on solar system abundances was founded, and summarizing the improvements that subsequently led to a crisis in the traditional ideas and to a new scenario in which reliable distributions of nuclei synthesized by slow neutron captures can be provided directly (and solely) by stellar models. In analyzing these last, we concentrate on recent work for low- and intermediate-mass stars in their final evolutionary stages, when they climb for the second time along the red giant branch. We summarize our knowledge of their evolution, mixing, and neutron capture nucleosynthesis, and we discuss some of the many open problems. In particular, we underline the fact that modeling the formation of the main neutron source still requires rather free parameterizations. The results of s-process calculations are then illustrated and compared with spectroscopic observations at different metallicities, with special attention to carbon stars.

Title:		The Status of the IRAIT Project
Authors:		Tosti, G.; Busso, M.; Straniero, O.; Abia, C.
Affiliation:		AA(Dipartimento di Fisica, Universitàdi Perugia, via A. Pascoli, 06123 Perugia, Italy ), AB(Dipartimento di Fisica, Universitàdi Perugia, via A. Pascoli, 06123 Perugia, Italy ), AC(INAF/Osservatorio di Collurania-Teramo, Italy, ), AD(Departamento de Física Teórica y del Cosmos, Universidad de Granada, Spain, )
Publication:		Memorie della Società Astronomica Italiana Supplement, v.5, p.385 (2004)
Publication Date:		00/2004
Origin:		MmSAI
Keywords:		Infrared: Instrumentation, Infrared: survey, Antarctic astronomy, Antarctic Permanent Observatories
Bibliographic Code:		2004MSAIS...5..385T

Abstract

The Antartic Plateau has been recognized to be one of the best sites from which to perform astronomical observations in the 2-20 mu m atmospheric windows, due to the low emission, and to the high transparency and stability of the sky. For Mid Infrared wavelengths, the possibility of passively cooling the equipment offers also an important opportunity to reduce the background, thus establishing conditions intermediate between those of ground-based observatories and of space. In order to exploit these exceptional characteristics we have designed the first permanent telescope for IR observations to be operated at the Concordia station, an Italo-French facility established at Dome C (3200m o.s.l.). We describe here the telescope, named IRAIT, and its mid infrared camera that should be operative on the Plateau in the 2006-2007 campaign.

Title:		First chemical analysis of extragalactic carbon stars
Authors:		Abia, C.; de Laverny, P.; Domínguez, I.; Straniero, O.; Cristallo, S.; Plez, B.
Affiliation:		AA(Dpto. de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain, ), AB(Observatoire de la Côte d'Azur, Dpt. Cassiopée UMR6202, 06304 Nice Cedex 4, France), AC(Dpto. de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain), AD(INAF-Osservatorio di Collurania, 64100 Teramo, Italy), AE(INAF-Osservatorio di Collurania, 64100 Teramo, Italy), AF(Université de Montpellier II, Montpellier, France)
Publication:		Memorie della Società Astronomica Italiana, v.75, p.607 (2004)
Publication Date:		00/2004
Origin:		MmSAI
Keywords:		AGB stars, carbon stars, nucleosynthesis, dwarf galaxies
Bibliographic Code:		2004MmSAI..75..607A

Abstract

We have performed the chemical analysis of extragalactic carbon stars from VLT/UVES spectra. The derived individual abundances of metals and s-elements as well as the well known distance of the selected stars in the Small Magellanic Cloud and the Sagittarius dwarf galaxy permit us to test current models of stellar evolution and nucleosynthesis during the asymptotic giant branch phase in low metallicity environments.

Title:		Draco 461, an intrinsic carbon star in a metal poor stellar population: 3^rd dredge up and mixing
Authors:		Domínguez, I.; Abia, C.; Straniero, O.
Affiliation:		AA(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain ), AB(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain ), AC(Main Astronomical Observatory, National Academy of Sciences, Zabolotnoho 27, Kiev-127 03680, Ukraine)
Publication:		Memorie della Società Astronomica Italiana, v.75, p.601 (2004)
Publication Date:		00/2004
Origin:		MmSAI
Keywords:		Carbon stars, AGB stars, nucleosynthesis, dwarf spheroidal galaxies
Bibliographic Code:		2004MmSAI..75..601D

Abstract

In July 2003 we observed the first Li-rich carbon star in a dwarf spheroidal galaxy. We compute stellar models for AGB stars and, by comparing them to the available photometric and spectroscopic data, conclude that D461 is an intrinsic carbon star, more massive and younger than the dominant stellar population of Draco.

Title:		An attempt to derive Mg isotopic ratios in carbon stars
Authors:		Zamora, O.; Abia, C.; de Laverny, P.; Domínguez, I.
Affiliation:		AA(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain, ), AB(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain), AC(Observatoire de la Côte d'Azur, Départament Cassiopée, UMR 6202, BP 4229, 06304 Nice Cedex 4, France), AD(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain)
Publication:		Memorie della Società Astronomica Italiana, v.75, p.596 (2004)
Publication Date:		00/2004
Origin:		MmSAI
Keywords:		Carbon stars, nucleosynthesis, stellar abundances
Bibliographic Code:		2004MmSAI..75..596Z

Abstract

We discuss the use of the spectral range near 7570 Å to determine the Mg isotopic ratios in carbon stars using the B^'² Sigma ⁺-X ² Sigma ⁺ system of the MgH molecule. We also compare with the spectral range near 5140 Å that has been commonly used in normal stars (oxygen-rich stars). The region near 5140 Å is not the better choice for carbon stars because it is very crowded with CN and C_2 molecular bands and the localization of the continuum is complicated. The range near 7570 Å is less blended with molecular bands. The continuum is easy to locate and the isotopic splitting between MgH isotopic absorptions is larger. Unfortunately, we are not able to reproduce accurately the observed spectrum in this region and, moreover, the synthetic spectrum is not sensitive to large variations in the isotopic ratios.

Title:		Lithium Abundances in the Atmospheres of SLR C-Giants WZ Cas and WX Cyg from Resonance and Subordinate Li I Lines
Authors:		Yakovina, Larisa A.; Pavlenko, Yakiv V.; Abia, Carlos
Affiliation:		AA(Main Astronomical Observatory of NASU, Golosiiv Woods, Kyiv-127, 03680, Ukraine; E-mail: ), AB(Main Astronomical Observatory of NASU, Golosiiv Woods, Kyiv-127, 03680, Ukraine; E-mail: ), AC(Dpt. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain; E-mail: )
Publication:		Astrophysics and Space Science, v. 288, Issue 3, p. 279-286 (2003). (Ap&SS Homepage)
Publication Date:		09/2003
Origin:		KLUWER
DOI:		10.1023/B:ASTR.0000006040.47162.b3
Bibliographic Code:		2003Ap&SS.288..279Y

Abstract

Lithium abundances in the atmospheres of the super Li-rich C-giants WZ Cas and WX Cyg are derived by the spectral synthesis technique using the Li I resonance line at λ670.8 nm and three subordinate lines at λλ 812.6, 610.4 and 497.2 nm. The differences between the Li abundances derived from the λ670.8 nm line and the λλ 497.2, 812.6 nm lines do not exceed +/- 0.5 dex. The lithium line at λ610.4 nm provides typically lower abundances than the resonance line (by ~ 1 dex). The mean LTE and NLTE Li abundances from three Li I lines (excluding λ610.4 nm) are 4.7, 4.9 for WZ Cas, and 4.6, 4.8 for WX Cyg, respectively.

Title:		Understanding AGB Carbon Star Nucleosynthesis from Observations
Authors:		Abia, C.; Domínguez, I.; Gallino, R.; Busso, M.; Straniero, O.; de Laverny, P.; Wallerstein, G.
Affiliation:		AA(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain.; ), AB(Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain.; ), AC(Dpto. di Fisica Generale, Universitá di Torino, 10125 Torino, Italy.; ), AD(Dpto. di Fisica, Universitá di Perugia, 06123 Perugia, Italy.; ), AE(Osservatorio di Collurania, 64100 Teramo, Italy.; ), AF(Observatoire de la Côte d'Azur, UMR6528, 06304 Nice Cedex 4, France.; ), AG(Dept. of Astronomy, University of Washington, Seattle WA 98195, USA.; )
Publication:		Publications of the Astronomical Society of Australia, Volume 20, Issue 4, pp. 314-323. (PASA Homepage)
Publication Date:		00/2003
Origin:		PASA
Keywords:		nuclear reactions, nucleosynthesis, abundances, stars: abundances, stars: AGB, stars: carbon, stars: evolution
DOI:		10.1071/AS03021
Bibliographic Code:		2003PASA...20..314A

Abstract

Recent advances in the knowledge of the evolutionary status of asymptotic giant branch (AGB) stars and of the nucleosynthesis processes occurring in them are discussed, and used to interpret abundance determinations for s-process elements, lithium and CNO isotopes in several types of AGB stars. We focus our attention mainly on carbon-rich AGB stars. By combining these different constraints we conclude that most carbon stars in the solar neighborhood are of low mass (M<=3 M_solar), their abundances being a consequence of the operation of thermal pulses and the third dredge-up. However, the observed abundances in carbon stars of the R and J types cannot be explained by this standard scenario. These stars may not be on the AGB, but possibly in the core-He burning phases; their envelopes may have been polluted with nuclear ashes of the core-He flash, followed by CNO re-processing enhancing ¹³C. Observational evidence suggesting the operation of non-standard mixing mechanisms during the AGB phase is also discussed.

Title:		A possible scientific case study for the future NIR spectrograph with IRAIT
Authors:		Abia, C.; Domínguez, I.
Affiliation:		AA(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain ), AB(Departamento de Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain )
Publication:		Memorie della Società Astronomica Italiana Supplement, v.2, p.105 (2003)
Publication Date:		00/2003
Origin:		MmSAI
Keywords:		AGB stars, nucleosynthesis, abundances
Bibliographic Code:		2003MSAIS...2..105A

Abstract

The atmospheric conditions in Antarctica for astronomical observations in the infrared are outstanding. The project to install a 0.8 m infrared telescope (IRAIT) in the base Dome C, to be exploited by Italian and French scientific teams, is aimed at making use of these extraordinary observation conditions. Here, we study the viability of a scientific case that could be performed with this telescope using an infrared spectrograph, namely a study of the ¹²C/¹³C ratio in AGB stars (O-rich & C-rich). The actual value of this isotopic ratio gives valuable information about the nucleosynthetic and mixing processes occurring within stars. Currently, there is some controversy concerning the typical (average) value of this ratio in carbon-rich and oxygen-rich AGB stars. The large isotopic splitting existing between ¹²CO and ¹³CO lines around 2.3 microns, and the fact that this spectral region is not very crowded, offers the opportunity to determine this isotopic ratio more accurately than from atomic or molecular features placed at optical wavelengths. For atmosphere parameters typical of AGB stars, we compute synthetic spectra of this molecular band simulating different spectral resolutions to determine the minimum resolution needed to successfully perform this study. Two Spanish institutions have recently expressed interest in joining the European astronomical team at Dome C and possibly in obtaining a low resolution infrared spectrograph for IRAIT.

Title:		The Chemical Composition of Carbon C(N) stars
Authors:		Abia, C.; Domínguez, I.; Gallino, R.; Masera, S.; Busso, M.; Straniero, O.; de Laverny, P.; Plez, B.
Publication:		CNO in the universe, Proceedings of a conference held in Saint-Luc, Valais, Switzerland, 10-14 September 2002. Edited by Corinne Charbonnel, Daniel Schaerer, and Georges Meynet. ASP Conference Series, Vol. 304. San Francisco, CA: Astronomical Society of the Pacific, 2003., p.122
Publication Date:		00/2003
Origin:		ADS
Bibliographic Code:		2003ASPC..304..122A

Abstract

A chemical study of normal Galactic C(N) carbon stars is presented. Abundances of Li, CNO isotopes and s-elements are derived. The derived abundances of s-elements nicely agree with theoretical s-process nucleosynthesis predictions during the AGB phase. However, the figures obtained for Li and the 12C/13C ratios might imply the existence of a non-standard mixing process during the AGB phase operating preferentially in low mass stars. The intrinsic or extrinsic nature of C(N) stars is also discussed.

Title:		s-Process Nucleosynthesis in Carbon Stars
Authors:		Abia, C.; Domínguez, I.; Gallino, R.; Busso, M.; Masera, S.; Straniero, O.; de Laverny, P.; Plez, B.; Isern, J.
Affiliation:		AA(Departamento de Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada, Spain; , ), AB(Departamento de Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada, Spain; , ), AC(Dipartimento di Fisica Generale, Universitá di Torino and Sezione INFN di Torino, via P. Giuria 1, 10125 Torino, Italy; ), AD(Dipartimento di Fisica, Università di Perugia, via Pascoli, 06123 Perugia, Italy; ), AE(Dipartimento di Fisica Generale, Università di Torino, via P. Giuria 1, 10125 Torino, Italy; ), AF(Osservatorio Astronomico di Collurania, I-64100 Teramo, Italy; ), AG(Observatoire de la Cote d'Azur, Departement Fresnel UMR 6528, Nice, France; ), AH(Université de Montpellier 2, Montpellier, France; ), AI(Institut d'Estudis Espacials de Catalunya (CSIC), Barcelona, Spain; )
Publication:		The Astrophysical Journal, Volume 579, Issue 2, pp. 817-831. (ApJ Homepage)
Publication Date:		11/2002
Origin:		UCP
ApJ Keywords:		Nuclear Reactions, Nucleosynthesis, Abundances, Stars: Abundances, Stars: AGB and Post-AGB, Stars: Carbon, Stars: Evolution
DOI:		10.1086/342924
Bibliographic Code:		2002ApJ...579..817A

Abstract

We present the first detailed and homogeneous analysis of the s-element content in Galactic carbon stars of N type. Abundances of Sr, Y, Zr (low-mass s-elements, or ls), Ba, La, Nd, Sm, and Ce (high-mass s-elements, or hs) are derived using the spectral synthesis technique from high-resolution spectra. The N stars analyzed are of nearly solar metallicity and show moderate s-element enhancements, similar to those found in S stars, but smaller than those found in the only previous similar study (Utsumi 1985), and also smaller than those found in supergiant post-asymptotic giant branch (post-AGB) stars. This is in agreement with the present understanding of the envelope s-element enrichment in giant stars, which is increasing along the spectral sequence M-->MS-->S-->SC-->C during the AGB phase. We compare the observational data with recent s-process nucleosynthesis models for different metallicities and stellar masses. Good agreement is obtained between low-mass AGB star models (M<~3 M_solar) and s-element observations. In low-mass AGB stars, the ¹³C(α, n)¹⁶O reaction is the main source of neutrons for the s-process a moderate spread, however, must exist in the abundance of ¹³C that is burnt in different stars. By combining information deriving from the detection of Tc, the infrared colors, and the theoretical relations between stellar mass, metallicity, and the final C/O ratio, we conclude that most (or maybe all) of the N stars studied in this work are intrinsic, thermally pulsing AGB stars; their abundances are the consequence of the operation of third dredge-up and are not to be ascribed to mass transfer in binary systems.

Title:		Galactic evolution of ⁷LI: observational clues for models
Authors:		Travaglio, C.; Randich, S.; Galli, D.; Abia, C.; Lattanzio, J.
Affiliation:		AA(Max-Planck-Institut für Astrophysik, Munich, Germany), AB(Osservatorio Astrofisico di Arcetri, Firenze, Italy), AC(Osservatorio Astrofisico di Arcetri, Firenze, Italy), AD(Universidad de Granada, Granada, Spain), AE(Monash University, Clayton, Victoria, Australia)
Publication:		Astrophysics and Space Science, v. 281, Issue 1, p. 219-220 (2002). (Ap&SS Homepage)
Publication Date:		07/2002
Origin:		KLUWER; SPRINGER
Keywords:		Galaxy: abundances, evolution; stars: nucleosynthesis, AGB, Mira, evolution, stars: nucleosynthesis
DOI:		10.1023/A:1019594200362
Bibliographic Code:		2002Ap&SS.281..219T

Abstract

Different stellar sources may have contributed to the ⁷Li enrichmentof the Galaxy: type-II supernovae, novae, and AGB stars. In the latter case, the interplay between the Hot Bottom Burning (HBB) process (via the Cameron-Fowler mechanism) and a very high mass-loss rate before the evolution off the AGB (the so-called ‘superwind’ phase), can lead to a significant production of ⁷Li from low- and intermediate-mass AGB stars (Travaglio et al., 2001). We have now undertaken an observational campaign aimed at constraining our stellar and Galactic models, with a twofold goal: (i) to assemble a compilation of high-resolution spectra of Galactic, unevolved (i.e. dwarfs), warm(spectral type F) stars, in a selected metallicity range (-1.0 ≤>[Fe/H] ≤ -0.3), using the ESO 1.5m telescope and the FEROS spectrograph; (ii) to carry out a Li survey among a sample of selected AGB stars, to investigate the possible correlation between⁷Li abundance (when detected) and mass-loss rate.

Title:		The s-process nucleosynthesis and the mass of carbon stars
Authors:		Abia, C.; Domínguez, I.; Busso, M.; Gallino, R.; Straniero, O.; Isern, J.; de Laverny, P.; Plez, B.
Publication:		In: Proceedings of the 11th Workshop on "Nuclear Astrophysics", Ringberg Castle, Tegernsee, Germany, February 11-16, 2002 / Wolfgang Hillebrandt and Ewald Müller (Eds.). MPA/P13, Garching b. München, Germany: Max-Planck-Institut für Astrophysik, 2002, p. 209 - 211
Publication Date:		04/2002
Origin:		ARI
ARI Keywords:		Nucleosynthesis, Carbon Stars, Masses
Bibliographic Code:		2002nuas.conf..209A

Abstract

Not Available

Title:		Zero-metal stellar yields, the IMF for population III and nucleosynthetic constraints
Authors:		Abia, C.; Domínguez, I.; Straniero, O.; Limongi, M.; Chieffi, A.; Isern, J.
Publication:		In: New quests in stellar astrophysics: the link between stars and cosmology. Proceedings of the international conference held in Puerto Vallarta, México, 26-30 March 2001, edited by Miguel Chávez, Alessandro Bressan, Alberto Buzzoni and Divakara Mayya. Astrophysics and Space Science Library, Vol. 274, Dordrecht: Kluwer Academic Publishers, ISBN 1-4020-0644-6, 2002, p. 59 - 62
Publication Date:		00/2002
Origin:		ARI
ARI Keywords:		Population III Stars
Abstract Copyright:		Kluwer
Comment:		ISBN: 1-4020-0644-6
Bibliographic Code:		2002ASSL..274...59A

Abstract

We study the nucleosynthesis constraints that the recent detection of metals in different components of the high redshift universe and the abundance ratios measured in the extremely metal-poor stars of our Galaxy, imposes on an early generation of stars (Population III).

Title:		The ⁸⁵Kr s-Process Branching and the Mass of Carbon Stars
Authors:		Abia, C.; Busso, M.; Gallino, R.; Domínguez, I.; Straniero, O.; Isern, J.
Affiliation:		AA(Departamento de Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada, Spain; ), AB(Osservatorio Astronomico di Torino, 10025 Pino Torinese, Italy; ), AC(Dipartimento di Fisica Generale, Università di Torino, Via P. Giuria 1, 10125 Torino, Italy; ), AD(Departamento de Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada, Spain; ), AE(Osservatorio Astronomico di Collurania, I-64100 Teramo, Italy; ), AF(Institut d'Estudis Espacials de Catalunya-CSIC, Barcelona, Spain; )
Publication:		The Astrophysical Journal, Volume 559, Issue 2, pp. 1117-1134. (ApJ Homepage)
Publication Date:		10/2001
Origin:		UCP
ApJ Keywords:		Nuclear Reactions, Nucleosynthesis, Abundances, Stars: Abundances, Stars: AGB and Post-AGB, Stars: Carbon
DOI:		10.1086/322383
Bibliographic Code:		2001ApJ...559.1117A

Abstract

We present new spectroscopic observations for a sample of C(N)-type red giants. These objects belong to the class of asymptotic giant branch stars, experiencing thermal instabilities in the He-burning shell (thermal pulses). Mixing episodes called third dredge-up enrich the photosphere with newly synthesized ¹²C in the He-rich zone, and this is the source of the high observed ratio between carbon and oxygen (C/O>=1 by number). Our spectroscopic abundance estimates confirm that, in agreement with the general understanding of the late evolutionary stages of low- and intermediate-mass stars, carbon enrichment is accompanied by the appearance of s-process elements in the photosphere. We discuss the details of the observations and of the derived abundances, focusing in particular on rubidium, a neutron density sensitive element, and on the s-elements Sr, Y, and Zr belonging to the first s-peak. The critical reaction branching at ⁸⁵Kr, which determines the relative enrichment of the studied species, is discussed. Subsequently, we compare our data with recent models for s-processing in thermally pulsing asymptotic giant branch stars, at metallicities relevant for our sample. A remarkable agreement between model predictions and observations is found. Thanks to the different neutron density prevailing in low- and intermediate-mass stars, comparison with the models allows us to conclude that most C(N) stars are of low mass (M<~3 M_solar). We also analyze the ¹²C/¹³C ratios measured, showing that most of them cannot be explained by canonical stellar models. We discuss how this fact would require the operation of an ad hoc additional mixing, currently called cool bottom process, operating only in low-mass stars during the first ascent of the red giant branch and, perhaps, also during the asymptotic giant branch.

Title:		Lithium in X-ray novae
Authors:		Isern, J.; Dominguez, I.; Abia, C.
Publication:		In: Exploring the gamma-ray universe. Proceedings of the Fourth INTEGRAL Workshop, 4-8 September 2000, Alicante, Spain. Editor: B. Battrick, Scientific editors: A. Gimenez, V. Reglero & C. Winkler. ESA SP-459, Noordwijk: ESA Publications Division, ISBN 92-9092-677-5, 2001, p. 69 - 71
Publication Date:		09/2001
Origin:		ARI
ARI Keywords:		LIGHT ELEMENTS, X-RAY NOVAE, GAMMA-RAYS
Abstract Copyright:		ESA
Comment:		ISBN: 92-9092-677-5
Bibliographic Code:		2001ESASP.459...69I

Abstract

The measurement of Li abundances larger than expected in the secondaries of some X-ray novae suggests that this element was created during the process of formation of the system or is freshly during X-ray outbursts. If this was the case, lithium abundances could provide interesting constraints to the physics of the core collapse or to the physics of accretion disks. In this paper we analyze the possibility that Li has been created by spallation by charged supra-thermal particles during "giant-like flares" associated to the system. If this was the case, a characteristic γ-ray pattern should appear together with an enhancement of Be and B.

Title:		The Implications of the New Z=0 Stellar Models and Yields on the Early Metal Pollution of the Intergalactic Medium
Authors:		Abia, C.; Domínguez, I.; Straniero, O.; Limongi, M.; Chieffi, A.; Isern, J.
Affiliation:		AA(Dept. Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada, Spain; ), AB(Dept. Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada, Spain; ), AC(Osservatorio Astronomico di Collurania, I-64100 Teramo, Italy; ), AD(Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monteporzio Catone, Roma, Italy; ), AE(Instituto di Astrofisica Spaziale (CNR), via Fosso Cavaliere, I-00133 Roma, Italy; ), AF(Institut d'Estudis Espacials de Catalunya-CSIC, Barcelona, Spain; )
Publication:		The Astrophysical Journal, Volume 557, Issue 1, pp. 126-136. (ApJ Homepage)
Publication Date:		08/2001
Origin:		UCP
ApJ Keywords:		Galaxies: Abundances, Galaxies: Formation, galaxies: intergalactic medium, Nuclear Reactions, Nucleosynthesis, Abundances, Stars: Luminosity Function, Mass Function
DOI:		10.1086/321660
Bibliographic Code:		2001ApJ...557..126A

Abstract

Motivated by the recent detection of metals in different components of the high-redshift universe and by the abundance ratios measured in the extremely metal-poor stars of our Galaxy, we study the nucleosynthesis constraints that this imposes on an early generation of stars (Population III). To do so we take into account the chemical yields obtained from homogeneous evolutionary calculations of zero-metal stars in the mass range 3<~m/M_solar<~40 (Limongi et al.; Chieffi et al.). We also consider the role played by metal-free very massive objects (m>100 M_solar). Using both analytical and numerical chemical evolution models, we confront model predictions from the different choices of the mass function proposed for Population III with the observational constraints. We show that low values of star formation efficiency (<1%) are required so as not to exceed the minimum metallicity ([C/H]~-2.4) measured in the high-redshift systems for any of the initial mass functions (IMFs) proposed. We also show that the observational constraints require Ω_sr<3×10^-3Ω_b, confirming previous claims that the possible contribution of the stellar remnants from Population III to the baryonic dark matter is insignificant. At present, however, the scarcity of abundance measurements for high-redshift systems does not permit us to put severe limitations on the nature of the initial mass function for Population III. In fact, overabundances of α-elements with respect to iron of the order of those measured in damped Lyα systems are obtained for any of the IMFs tested. Nevertheless, to account for the very large [C, N/Fe] ratios found in a considerable number of extremely metal-poor stars of our Galaxy, an IMF peaking at the intermediate stellar mass range (4-8 M_solar) is needed.

Title:		The role of /Z=0 AGB stars on the early chemical enrichment
Authors:		Domínguez, I.; Abia, C.; Straniero, O.; Chieffi, A.; Limongi, M.
Publication:		Nuclear Physics A, Volume 688, Issue 1-2, p. 399-401.
Publication Date:		05/2001
Origin:		ELSEVIER
DOI:		10.1016/S0375-9474(01)00736-9
Bibliographic Code:		2001NuPhA.688..399D

Abstract

We present theoretical evolutionary models for Z=0 stars in the mass range 4< M/Mo <8 from the pre-main sequence up to the AGB phase. Contrary to previous calculations we found that these stars develop normal thermal pulses and third dredge-up episodes. Special attention is devoted to analyze the chemical enrichment in the envelope due to the above mechanisms. As a consequence, we show that these stars become carbon and nitrogen rich. Using different IMFs proposed in the literature for the Population III stars, we study their contribution to the pre-galactic chemical enrichment. It is found that Z=0 AGB stars could significantly contribute to 7Li, 12C and 14N and produce extreme non-solar 24Mg/25Mg/26Mg ratios. However, the net contribution is very sensitive to the IMF adopted and to the fraction of primordial matter which goes into stars.

Title:		Pollution from primordial stars
Authors:		Straniero, Oscar; Dominguez, Inma; Abia, Carlos; Limongi, Marco; Chieffi, Alessandro
Publication:		Memorie della Società Astronomica Italiana (ISSN 0037-8720), Vol. 72, N. 2, p. 265 - 275 (2001). In: Salting the early soup: trace nuclei from stars to the solar system. Torino, June 21 - 22, 2000, edited by M. Busso and R. Gallino
Publication Date:		00/2001
Origin:		ARI
ARI Keywords:		Primordial Stars, Population III Stars
Bibliographic Code:		2001MmSAI..72..265S

Abstract

Constraints on the mass function of the first stellar population can be obtained by comparing the nucleosynthesis predicted by appropriate stellar models with the abundances of heavy elements recently measured in the Lyman-α forest, damped Lyman-α systems and in the very metal-poor stars of the Milky Way. Here we report some preliminary results of an investigation devoted to the comprehension of the early galactic nucleosynthesis.

Title:		NLTE Formation of LiI Lines in Atmospheres of Cool C-Rich Giants (CD-ROM Directory: contribs/pavlen1)
Authors:		Pavlenko, Ya.; Abia, C.; de Laverny, P.
Publication:		11th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun, ASP Conference Proceedings, Vol. 223. Edited by Ramon J. Garcia Lopez, Rafael Rebolo, and Maria Rosa Zapaterio Osorio. San Francisco: Astronomical Society of the Pacific, ISBN: 1-58381-055-2, p.850
Publication Date:		00/2001
Origin:		ADS
Comment:		ISBN: 1-58381-055-2
Bibliographic Code:		2001ASPC..223..850P

Abstract

Not Available

Title:		The First Stars: Evolution and Nucleosynthesis
Authors:		Domínguez, Inma; Abia, Carlos; Straniero, Oscar; Chieffi, Alessandro; Limongi, Marco
Affiliation:		AA(Universidad de Granada, Granada, Spain), AB(Universidad de Granada, Granada, Spain), AC(Osservatorio Astronomico di Collurania, Teramo, Italy), AD(Istituto di Astrofisica Spaziale, Roma, Italy), AE(Osservatorio Astronomico di Roma, Monteporzio, Italy)
Publication:		Astrophysics and Space Science Supplement, v. 277, p. 161-164 (2001).
Publication Date:		00/2001
Origin:		KLUWER
Keywords:		STELLAR EVOLUTION, POP. III, AGB, NUCLEOSYNTHESIS
DOI:		10.1023/A:1012793425129
Bibliographic Code:		2001ApSSS.277..161D

Abstract

We have computed stellar models of metal-free (Z=0) intermediate mass stars (4-8 M_odot). We have found, for the first time, that these stars do experience the thermal pulse phase and enrich the envelope with He, C, primary N and some O and Li. Adopting an IMF obtained for Z=0 stars, we show that Pop. III intermediate mass stars could have contributed significantly to the early nitrogen and carbon galactic enrichment. Furthermore, local contaminations would be very relevant.

Title:		¹²C/¹³C Ratios and Li Abundances in Low-Mass C Stars
Authors:		Abia, Carlos; Isern, Jordi
Publication:		The Carbon Star Phenomenon, Proceedings of the 177th Symposium of the International Astronomical Union, held in Antalya, Turkey, May 27-31, 1996. Edited by Robert F. Wing, Astronomy Department, The Ohio State University, Columbus, USA. International Astronomical Union Symposia, Volume 177 Kluwer Academic Publishers, Dordrecht, 2000., p.89
Publication Date:		06/2000
Origin:		ADS
Bibliographic Code:		2000IAUS..177...89A

Abstract

Not Available

Title:		The Chemical Composition of Carbon Stars. II. The J-Type Stars
Authors:		Abia, C.; Isern, J.
Affiliation:		AA(Dpt. Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada, Spain; ), AB(Institut d'Estudis Espacials de Catalunya - CSIC, c/ Gran Capitá 2-4, E-08034 Barcelona, Spain. )
Publication:		The Astrophysical Journal, Volume 536, Issue 1, pp. 438-449. (ApJ Homepage)
Publication Date:		06/2000
Origin:		UCP
ApJ Keywords:		Nuclear Reactions, Nucleosynthesis, Abundances, Stars: Abundances, Stars: Carbon, Stars: Evolution
DOI:		10.1086/308932
Bibliographic Code:		2000ApJ...536..438A

Abstract

Abundances of lithium, heavy elements, and carbon isotope ratios have been measured in 12 J-type Galactic carbon stars. The abundance analysis shows that in these stars the abundances of s-process elements with respect to the metallicity are nearly normal. Tc is not present in most of them, although upper limits have been derived for WZ Cas and WX Cyg, perhaps two SC-type rather than J-type carbon stars. The Rb abundances, obtained from the resonance λ7800 Rb I line, are surprisingly low, probably owing to strong non-LTE effects in the formation of this line in cool carbon-rich stars. Lithium and ¹³C are found to be enhanced in all the stars. These results together with the nitrogen abundances and oxygen isotope ratios measured by Lambert et al. and Harris et al. are used to discuss the origin of J stars. The luminosity and variability class of the stars studied would indicate that they are low-mass (M<~2-3 M_solar), less evolved objects than the normal carbon stars, although the presence of some luminous (M_bol<-5.5) J stars in our Galaxy (WZ Cas may be an example) and in other galaxies, suggests the existence of at least two types of J stars, with different formation scenarios depending upon the initial mass of the parent star. Standard evolutionary AGB models are difficult to reconcile with all the observed chemical characteristics. In fact, they suggest the existence of an extra mixing mechanism that transports material from the convective envelope down to hotter regions where some nuclear burning occurs. This mechanism would act preferably on the early-AGB phase in low-mass stars. Mixing at the He-core flash and the binary system hypothesis are also discussed as alternatives to the above scenario.

Title:		The chemical composition of the rare J-type carbon stars.
Authors:		Abia, C.; Isern, J.
Publication:		Mem. Soc. Astron. Ital., 71, 631-638 (2000)
Publication Date:		00/2000
Origin:		SIMBAD
Bibliographic Code:		2000MmSAI..71..631A

Abstract

Abundances of lithium, heavy elements and carbon isotope ratios have been derived in 12 J-type galactic carbon stars. The abundance analysis shows that in these stars the abundances of s-process elements with respect to the metallicity are nearly solar. Tc is not present in most of them. The Rb abundances, obtained from the resonance 7800 {\AA} RbI line, are surprisingly low, probably due to stroong non-LTE effects. Lithium and $^{13}$C are found to be enhanced in all the stars. These results are used to discuss the origin of J-stars.

Title:		Understanding the Li Production in AGB stars: the J-type Stars
Authors:		Abia, C.; Isern, J.
Publication:		The Light Elements and their Evolution, Proceedings of IAU Symposium 198, held 22-26 Nov 1999, Natal, Brazil. Edited by L. da silva, R. de Medeiros, &M Spite, 2000., p.370
Publication Date:		00/2000
Origin:		ADS
Bibliographic Code:		2000IAUS..198..370A

Abstract

Not Available

Title:		The formation of lithium lines in the atmospheres of super Li-rich AGB stars
Authors:		Abia, C.; Pavlenko, Y.; de Laverny, P.
Affiliation:		AA(Dpt. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain ()), AB(The Main Astronomical Observatory of NAS, Golosiiv woods, 252650 Kyiv-22, Ukraine ()), AC(Observatoire de la Cote d'Azur, Dpt. Fresnel UMR 6528, B.P. 4229, 06304 Nice Cedex 04, France ())
Publication:		Astronomy and Astrophysics, v.351, p.273-282 (1999) (A&A Homepage)
Publication Date:		11/1999
Origin:		A&A
A&A Keywords:		STARS: ABUNDANCES, STARS: AGB AND POST-AGB, STARS: CARBON
Bibliographic Code:		1999A&A...351..273A

Abstract

The formation of lithium lines in the atmosphere of C-rich giants is discussed. LTE and NLTE approximations are used to model lithium lines in the spectra of super Li-rich AGB stars. The system of equations of the statistical balance of neutral Li in plane-parallel model atmospheres is solved for a 20-level atom model. JOLA and line-by-line models of molecular absorption are used to compute synthetic spectra as well as the opacity in the frequencies of bound-bound and bound-free transitions of the lithium lines. Curves of growth and synthetic spectra are computed in LTE and NLTE for several model atmospheres of different {T_eff} and C/O ratios for four lithium absorptions, namely: the lambda 4603, lambda 6104, lambda 6708 and lambda 8126 Å Li I lines. The sensitivity of NLTE effects on {T_eff} and the C/O ratio is discussed. We found that NLTE mainly affects the resonance line doublet (lambda6708 ) while the impact of NLTE effects on the lithium subordinate lines, formed in the inner regions of C-rich giant atmospheres, is rather weak. Therefore the use of these lines is recommended for Li determination in AGB stars. However, in no case can we properly account for the formation of Li lines in AGB stars until sphericity, velocity stratifications, dust, chromospheres and other related phenomena, which are in fact present in AGB star atmospheres, are considered. Our results are used to derive Li abundances in three super-Li rich C-stars taking into account NLTE effects. Finally, the net Li yield from this class of stars into the interstellar medium is reconsidered.

Title:		Lithium Abundances in AGB Stars: a Probe to Test Convective Theories and Nucleosynthesis
Authors:		Abia, C.; Isern, J.
Publication:		Stellar Structure: Theory and Test of Connective Energy Transport, ASP Conference Series, Vol. 173. Edited by Alvaro Gimenez, Edward F. Guinan, and Benjamin Montesinos. Astronomical Society of the Pacific (San Francisco), ISBN: 1-886733-95-3 (1999), p.285
Publication Date:		00/1999
Origin:		ADS
Comment:		ISBN: 1-886733-95-3
Bibliographic Code:		1999ASPC..173..285A

Abstract

Not Available

Title:		The role of gravitational supernovae in the Galactic evolution of the Li, Be and B isotopes
Authors:		Abia, Carlos; Isern, Jordi; Lisenfeld, Ute
Affiliation:		AA(Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, 18071 Granada, Spain), AB(Institut d'Estudis Espacials de Catalunya/CSIC, Gran Capita 2-4, 08034 Barcelona, Spain), AC(IRAM, Avda Divina Pastora 7, Nucleo Central, 18012 Granada, Spain)
Publication:		Monthly Notices of the Royal Astronomical Society, Volume 299, Issue 4, pp. 1007-1012. (MNRAS Homepage)
Publication Date:		10/1998
Origin:		MNRAS
MNRAS Keywords:		NUCLEAR REACTIONS, NUCLEOSYNTHESIS, ABUNDANCES, SUPERNOVAE: GENERAL, GALAXY: ABUNDANCES
DOI:		10.1046/j.1365-8711.1998.01821.x
Bibliographic Code:		1998MNRAS.299.1007A

Abstract

The observed Be and B relationships with metallicity clearly support the idea that both elements have a primary origin and that they are produced by the same class of objects. Spallation by particles accelerated during gravitational supernova events (SNII, SNIb/c) seems to be a likely origin. We show, in the context of a model of chemical evolution, that it is possible to solve the Li, Be and B abundance puzzle with the yields recently proposed by Ramaty et al., provided that SNII are unable to accelerate helium nuclei significantly and that different mechanisms are allowed to act simultaneously.

Title:		Heavy-element abundances in seven SC stars and several related stars
Authors:		Abia, C.; Wallerstein, G.
Affiliation:		AA(Granada, Univ.), AB(Washington, Univ., Seattle)
Publication:		Royal Astronomical Society, Monthly Notices, vol. 293, p. 89 (MNRAS Homepage)
Publication Date:		01/1998
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		HEAVY ELEMENTS, ABUNDANCE, S STARS, B STARS, K STARS, M STARS, CARBON STARS, STELLAR COMPOSITION, NUCLEAR FUSION, ASYMPTOTIC GIANT BRANCH STARS, NONEQUILIBRIUM THERMODYNAMICS, SPECTRAL LINE WIDTH, RUBIDIUM
DOI:		10.1046/j.1365-8711.1998.01157.x
Bibliographic Code:		1998MNRAS.293...89A

Abstract

We employ spectra of resolution 20-35,000 of seven SC stars, four S stars, two Ba stars, and two K-M stars to derive abundances of a variety of elements from Sr to Eu relative to iron. Special attention is paid to Rb and Tc, and to the ratio of the heavy s-process species to the light s-process elements. Abundances are derived in LTE, both by using model atmospheres in which the carbon and oxygen abundances are nearly equal and by using curves of growth. Spectrum synthesis is used for critical lines, such as the 5924-A line of Tc and the 7800-A line of Rb. For most of the heavy-element stars, the enhancement of the s-process elements is about a factor of 10. The ratio of the heavy to light s-process species is not far from solar, except for RR Her, for which the same ratio is + 0.45 dex. For Tc the blending by other lines is severe. While we have probably detected the 5924-A line, we can only present abundances in the less-than-or-equal-to category.

Title:		New and accurate Li abundance determinations in super Li-rich AGB stars
Authors:		Abia, C.; de Laverny, P.; Pavlenko, Y.
Affiliation:		AA(Dpt. Fisica Teorica y del Cosmos, Universidad de Granada, Granada, Spain ), AB(GRAAL, Universite Montpellier II, Montpellier, France), AC(The Main Astronomical Observatory of Ukranian Academy of Sciences, Golosiiv woods, 252650 Kyiv-22, Ukraine)
Publication:		Asymptotic Giant Branch Stars, IAU Symposium 191 Poster Session, #P1-01, held in Montpellier, France, Aug 28 - Sept 1, 1998.
Publication Date:		00/1998
Origin:		AUTHOR
Bibliographic Code:		1998IAUS..191P.101A

Abstract

Super lithium-rich AGB stars constitute the sole observational evidence of a stellar production of lithium. Abundance determinations report values as high as Li/H ~10^{-7} in their atmospheres (i.e. more than 10-100 times the cosmic abundance), therefore these stars might represent an important source of lithium in the galaxies. However most of these abundance analyses are based on the study of the resonance line of LiI 6708 Angstroms which usually is very strong or near saturation even in AGB stars with normal lithium abundances. Here we have used high-resolution and high signal-to-noise ratio spectra of three well known super Li-rich carbon stars (WZ Cas, WX Cyg and IY Hya) to derive LTE/N-LTE lithium abundances using two other accessible less-intense Li lines at 6103 and 8126 Angstroms for the first time in AGB stars. We show that N-LTE effects are very important for the resonance line. Furthermore, the core of the 6708 Angstroms line forms very high in the atmosphere of AGB stars where the structure of the atmosphere is almost unknown. That excludes the use of this line for realistic Li abundance determinations in AGB stars. On the contrary, we found that N-LTE effects are weak for the two other lines. Although it is saturated, the subordinate Li line at 8126 Angstroms is recommended to derive abundances in Li-rich AGB stars.

Title:		¹²C/¹³C ratios and Li abundances in C stars: evidence for deep mixing?
Authors:		Abia, C.; Isern, J.
Publication:		Mon. Not. R. Astron. Soc., Vol. 289, No. 4, p. L11 - L15 (MNRAS Homepage)
Publication Date:		08/1997
Origin:		ARI
ARI Keywords:		Carbon Stars: Metal Abundances, Carbon Stars: Lithium, Carbon Stars: Isotopic Composition, Carbon Stars: Stellar Evolution
MNRAS Keywords:		nuclear reactions, nucleosynthesis, abundances - stars: abundances - stars: carbon
Bibliographic Code:		1997MNRAS.289L..11A

Abstract

High-resolution spectra are used to derive Li abundances and ¹²C/¹³C ratios for 44 Galactic C stars. It is found that Li-rich stars [log ɛ(Li) > 1] usually have low ¹²C/¹³C ratios (<15). The great majority of the Li-rich and low ¹²C/¹³C stars are of J type, although this correlation can also be found in normal (N-type) C stars. If these stars were indeed low-mass C stars, these results would require the existence of a deep-mixing mechanism able to operate in low-mass (M ⪉ 2 M_sun) C stars as an alternative for Li production by the hot bottom burning mechanism proposed in asymptotic giant branch stars with larger mass. We show observational evidence suggesting that high mass loss appears to act against such a mechanism.

Title:		The puzzling origin of LiBeB isotopes presented by J. Isern
Authors:		Isern, J.; Hernanz, M.; Abia, C.; Jose, J.
Publication:		Frontier Objects in Astrophysics and Particle Physics, Proceedings of the Vulcano Workshop 1996, Vulcano, Italy, May 27 - June 1, 1996, Edited by F. Giovannelli and G. Mannocchi. Publisher: Bologna, Italy: Italian Physical Society, 1997, Series: Italian Physical Society conference Proceedings Series Vol no: 57, ISBN: 8877940964, p.113
Publication Date:		00/1997
Origin:		ADS
Comment:		ISBN: 8877940964
Bibliographic Code:		1997foap.conf..113I

Abstract

Not Available

Title:		Clues for Lithium Production in Galactic C Stars: The ¹²C/¹³C Ratio
Authors:		Abia, C.; Isern, J.
Publication:		Astrophysical Journal v.460, p.443 (ApJ Homepage)
Publication Date:		03/1996
Origin:		APJ
ApJ Keywords:		STARS: ABUNDANCES, STARS: CARBON, STARS: AGB AND POST-AGB
DOI:		10.1086/176982
Bibliographic Code:		1996ApJ...460..443A

Abstract

High-resolution spectroscopy is presented for 11 Population I Galactic carbon stars (C stars). Carbon isotopic ratios (¹²C/¹³C) and lithium abundances are derived from LTE synthetic spectra. It is found that the ¹³C-rich stars are also Li-rich. We argue that the Li and ¹³C enrichment in Galactic C stars might be produced by a similar mechanism. Evidence of the operation of hot bottom burning (HBB) is found in the ¹³C-rich stars. However, theoretical models for asymptotic giant branch stars do not predict the simultaneous existence of HBB and Li production in stars with initial masses M ˜2 M_sun, which is the typical initial mass of the stars analyzed here. We briefly discuss the observations in terms of the current models for C stars.

Title:		Galactic evolution of the light element isotopes revisited.
Authors:		Abia, C.; Isern, J.; Canal, R.
Publication:		Astronomy and Astrophysics, v.298, p.465 (A&A Homepage)
Publication Date:		06/1995
Origin:		A&A via CDS; KNUDSEN
A&A Keywords:		NUCLEOSYNTHESIS, COSMIC RAYS, GALAXY: ABUNDANCES, GALAXY: EVOLUTION
Bibliographic Code:		1995A&A...298..465A

Abstract

We have studied the evolution of the light element abundances by means of a relatively simple model of galactic chemical evolution. It is shown that it is possible to reasonably account for the element abundances and abundance ratios recently determined in stars on the grounds of the standard galactic cosmic ray nucleosynthesis and the stellar production of ^7^Li in low mass AGB stars. The apparent constancy of the ^7^Li/^6^Li ratio from the epoch of the Solar System formation (12.5) until now can be naturally explained with this stellar source of Li. However, if the overabundances of Be (and perhaps B) found in very metal deficient stars are confirmed by further observations, another origin besides cosmic ray nucleosynthesis must be considered to explain the early evolution of the Be (B?) abundances. A primordial production of Be is suggested.

Title:		Constraints on the Galactic Evolution of the Li Abundance from the
Authors:		Abia, C.; Isern, J.; Canal, R.
Publication:		The Light Element Abundances, Proceedings of an ESO/EIPC Workshop Held in Mar
Publication Date:		00/1995
Origin:		ADS
Bibliographic Code:		1995lea..conf..346A

Abstract

Not Available

Title:		A Catalog of li Abundances and Equivalent Widths in a Sample of Galactic C-Stars
Authors:		Boffin, H. M. J.; Abia, C.; Isern, J.; Rebolo, R.
Publication:		ASTRON. AND ASTROPHYS. SUPPL. V.102, NO. 2/DECI, P. 361, 1993 (A&AS Homepage)
Publication Date:		12/1993
Origin:		KNUDSEN
A&A Keywords:		stars: abundances, stars: late-type
Bibliographic Code:		1993A&AS..102..361B

Abstract

In the first two papers of this series, we derived and discussed the abundances of lithium in a sample of 161 galactic carbon stars. Here, we extend this sample to 203 stars and we present the spectra from which these abundances were derived, as well as a tabulation of the equivalent widths of the λ6708 Å feature. A comparison of our measurements with the equivalent widths from other authors is also made. Finally, we briefly discuss the possible variation in time of the lithium line in one star, R Lep.

Title:		Li abundances in galactic C-stars (Boffin+ 1993)
Authors:		Boffin, H. M. J.; Abia, C.; Isern, J.; Rebolo, R.
Publication:		VizieR On-line Data Catalog: J/A+AS/102/361. Originally published in: 1993A&AS..102..361B
Publication Date:		09/1993
Origin:		SIMBAD
Keywords:		Abundances, Equivalent widths, Stars: carbon
Comment:		table1.dat 201x73 Li abundances and equivalent widths; of galactic C-stars
Bibliographic Code:		1993yCat..41020361B

Abstract

The equivalent widths and abundances of Lithium in galactic carbon stars are presented in Table 1. The observations were made during 1990 and 1991 in 3 different observatories: Roque de los Muchachos and Calar Alto (Spain), and La Silla (Chile). The resolving power of the spectra is 15000-2000 for the spanish observations, and about 60000 for the stars observed at La Silla. (1 data file).

Title:		On the li Production by Galactic C-Stars
Authors:		Abia, C.; Isern, J.; Canal, R.
Publication:		ASTRONOMY AND ASTROPHYSICS V.275, NO. 1/AUG(I), P. 96, 1993 (A&A Homepage)
Publication Date:		08/1993
Origin:		KNUDSEN
A&A Keywords:		Lithium, C stars, nucleosynthesis
Bibliographic Code:		1993A&A...275...96A

Abstract

From a flux-limited sample of galactic carbon stars we estimate the contribution of such stars to the galactic abundance of lithium. The average Li production rate is found to be < m^ṡ₇ > = 4.5 × 10^-14M_sunyr^-1 per C star and it is mainly determined by the number of super-rich Li stars (log ɛ(Li) > 4). We show that, given a plausible choice of the IMF and the history of the star formation rate, the yield over the galactic life is M_Li ≍ 30 M_sun. The stellar mass loss rate and the exact Li abundance in the rich and super-rich Li stars (log ɛ(Li) > 1) are the main sources of uncertainty (since just one star, IY Hya, might well account for almost the whole current Li production in the solar neighbourhood!). Otherwise, that value only amounts to a contribution of 30% to the current galactic Li and other sources of Li besides, big-bang and cosmic rays, are thus needed to account for the present galactic abundance of this element.

Title:		Lithium Abundances in a Flux-Limited Sample of Galactic Carbon Stars
Authors:		Abia, C.; Boffin, H. M. J.; Isern, J.; Rebolo, R.
Publication:		ASTRONOMY AND ASTROPHYSICS V.272, NO. 2/MAYII, P. 455, 1993 (A&A Homepage)
Publication Date:		05/1993
Origin:		KNUDSEN
A&A Keywords:		stars: abundances, stars: evolution, stars: late-type
Bibliographic Code:		1993A&A...272..455A

Abstract

Lithium abundances, or upper limits, have been derived for 161 galactic carbon stars, selected from the Two Micron Sky Survey, using high resolution, high signal to noise ratio spectra and synthetic spectrum fitting. Fourteen of these C-stars present surface lithium abundances [log ɛ(Li) ≥ 1.0] higher than theoretically expected during the AGB phase, but only three are super-rich lithium stars [log ɛ(Li) >4], which confirms the scarce number of galactic C-stars (˜2%) of this type. The average masses of the sample stars suggests the plume mixing, instead of the hot bottom burning mechanism, as the nucleosynthetic scenario for the production of lithium in these stars. However, the expected theoretical correlations among lithium abundances and ¹²C/¹³C, C/O ratios do not show up. The lithium abundance distribution of the remaining stars shows a pronounced peak at log ɛ(Li) ≍ -0.5 suggesting, when compared to those in M and SC stars, that no important lithium depletion occurs during the transition from M to C-star.

Title:		Lithium in a sample of galactic C-stars.
Authors:		Abia, C.
Publication:		Symposium in Honour of Hubert Reeves' 60th birthday: Origin and evolution of the elements, p. 212 - 215
Publication Date:		01/1993
Origin:		ARI
ARI Keywords:		Lithium: Carbon Stars
Bibliographic Code:		1993oee..conf..212A

Abstract

Not Available

Title:		O/fe VS Fe/h at Low Metallicity
Authors:		Abia, C.; Canal, R.; Isern, J.
Publication:		Elements and the Cosmos. Proceedings of the 31st. Herstmonceux Conference, held in Cambridge, England July 16-20, 1990. Editors, Mike G. Edmunds, Roberto Terlevich; Publisher, Cambridge University Press, New York, 1992.ISBN # 0-52141475. LC # QB 980 .E435, P. 129, 1992
Publication Date:		00/1992
Origin:		ADS
Comment:		ISBN: 0-52141475
Bibliographic Code:		1992eatc.conf..129A

Abstract

Not Available

Title:		IY Hya - A new super Li-rich carbon star
Authors:		Abia, C.; Boffin, H. M. J.; Isern, J.; Rebolo, R.
Affiliation:		AA(Bruxelles, Universite Libre, Brussels, Belgium; CSIC, Centre d'Estudis Avancats de Blanes, Spain), AB(Bruxelles, Universite Libre, Brussels, Belgium), AC(CSIC, Centre d'Estudis Avancats de Blanes; Institut d'Estudis Catalans, Barcelona, Spain), AD(Instituto de Astrofisica de Canarias, La Laguna, Spain)
Publication:		Astronomy and Astrophysics (ISSN 0004-6361), vol. 245, no. 1, May 1991, p. L1-L4. Research supported by DGICYT and CSIC. (A&A Homepage)
Publication Date:		05/1991
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		CARBON STARS, HERTZSPRUNG-RUSSELL DIAGRAM, LITHIUM, METALLIC STARS, HEAVY ELEMENTS, INTERSTELLAR MATTER, STELLAR STRUCTURE
Bibliographic Code:		1991A&A...245L...1A

Abstract

The discovery is reported of a new lithium super-rich carbon star, IY Hya, and the Li abundance in three other carbon stars (T Sgr, WZ Cas and WX Cyg), previously known as super Li-rich stars is derived. All these stars show abundances in the range log N(Li) = 4.5 (i.e., 10 to 100 times higher than the present cosmic value). Two of them (WX Cyg and T Sgr) present variations in the Li feature when compared with previous studies.

Title:		On the O/Fe versus Fe/H relationship and the progenitors of type I supernovae
Authors:		Abia, C.; Canal, R.; Isern, J.
Affiliation:		AA(Instituto de Astrofisica de Canarias, La Laguna, Spain; Institut d'Astronomie, d'Astrophysique et de Geophysique, Brussels, Belgium), AB(Barcelona, Universidad; Societat Catalana de Fisica, Spain), AC(Societat Catalana de Fisica, Barcelona; Blanes, Centre d'Estudis Avancats, Spain)
Publication:		Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 366, Jan. 1, 1991, p. 198-202. Research supported by CICYT. (ApJ Homepage)
Publication Date:		01/1991
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		IRON, NUCLEAR ASTROPHYSICS, STELLAR EVOLUTION, STELLAR MODELS, SUPERNOVAE, ABUNDANCE, SOLAR NEIGHBORHOOD, STELLAR COMPOSITION, STELLAR MASS ACCRETION, WHITE DWARF STARS, WOLF-RAYET STARS
DOI:		10.1086/169552
Bibliographic Code:		1991ApJ...366..198A

Abstract

The new observational O/Fe versus Fe/H abundance relationship for halo stars is studied in terms of several models of chemical evolution for the solar neighborhood. Nucleosynthesis products from type I (both Ia and Ib) and Type II SNs are taken into account. The behavior of the O/Fe ratio for halo and disk stars is well reproduced by assuming (1) a lower iron production in SN II than in previous theoretical prescriptions, (2) the coalescence by gravitational wave radiation of two CO white dwarfs as the scenario for type Ia supernovae, and (3) stars in the Wolf-Rayet stage as progenitors of type Ib supernovae. Nevertheless, the best agreement with the observations is obtained by adopting an IMF favoring massive star formation only at very early epochs in the life of the Galaxy. Model predictions from other plausible scenarios for the origin of type I supernovae are also discussed.

Title:		Oxygen abundances in unevolved metal-poor stars.
Authors:		Rebolo, R.; Abia, C.
Publication:		Symposium in Celebration of the 50. Anniversary of McDonald Observatory of the University of Texas at Austin: Frontiers of stellar evolution, p. 615
Publication Date:		00/1991
Origin:		ARI
ARI Keywords:		Metal-Poor Stars: Oxygen
Bibliographic Code:		1991ASPC...20Q.615R

Abstract

Not Available

Title:		Lithium in carbon stars.
Authors:		Boffin, H. M. J.; Abia, C.
Affiliation:		AA(Institut d'Astrophysique, Universite Libre de Bruxelles, Belgium) AB(Institut d'Astrophysique, Universite Libre de Bruxelles, Belgium & Centre d'Estudis Avancats de Blanes, CSIC, Spain)
Publication:		The Messenger, vol. 62, p. 56-59 (Msngr Homepage)
Publication Date:		12/1990
Origin:		ARI; ESO
ARI Keywords:		Stellar Chromospheres: Lithium, Stellar Chromospheres: Spectra
Bibliographic Code:		1990Msngr..62...56B

Abstract

Not Available

Title:		The early nucleosynthesis of O and Fe
Authors:		Abia, C.; Canal, R.; Isern, J.
Affiliation:		AA(Instituto de Astrofisica de Canarias, La Laguna, Spain), AB(Barcelona, Universidad; Institut d'Estudis Catalans, Spain), AC(CSIC, Centro d'Estudis Avancats de Blanes; Institut d'Estudis Catalans, Barcelona, Spain)
Publication:		(IAU, European Regional Astronomy Meeting, 11th, La Laguna, Spain, July 3-8, 1989) Astrophysics and Space Science (ISSN 0004-640X), vol. 170, no. 1-2, Aug. 1990, p. 361-365. (Ap&SS Homepage)
Publication Date:		08/1990
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		DWARF STARS, HALOS, HYDROGEN, IRON, NUCLEAR FUSION, OXYGEN, STELLAR EVOLUTION, STELLAR MODELS, GRAVITATIONAL WAVES, LIGHT CURVE, MILKY WAY GALAXY, STAR FORMATION, STELLAR MASS EJECTION, SUPERNOVAE, WHITE DWARF STARS, WOLF-RAYET STARS
DOI:		10.1007/BF00652693
Bibliographic Code:		1990Ap&SS.170..361A

Abstract

The new observational O/Fe vs Fe/H relationship in halo dwarfs is analyzed in terms of a model of chemical evolution for the solar neighborhood. The role of nucleosynthesis prescriptions for SN II and SN I (both Ia and Ib) is analyzed. It is shown that, by adopting iron yields for SN II according to the observations of SN 1987A and by assuming double degenerate systems to be the progenitors of SN Ia and Wolf-Rayet stars to be the progenitors of SN Ib, it is possible to reproduce quite well the behavior of the O/Fe ratio for halo and disk stars. Nevertheless, best agreement is obtained when introducing in addition a variable IMF during the halo evolution.

Title:		Oxygen abundances in unevolved metal-poor stars - Interpretation and consequences
Authors:		Abia, C.; Rebolo, R.
Affiliation:		AA(Instituto de Astrofisica de Canarias, La Laguna, Spain), AB(Instituto de Astrofisica de Canarias, La Laguna, Spain)
Publication:		Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 347, Dec. 1, 1989, p. 186-194. (ApJ Homepage)
Publication Date:		12/1989
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		ABUNDANCE, GALACTIC EVOLUTION, METALLICITY, MILKY WAY GALAXY, OXYGEN, STELLAR COMPOSITION, ASTRONOMICAL SPECTROSCOPY, CHEMICAL EVOLUTION, DWARF STARS, ERROR ANALYSIS, GALACTIC STRUCTURE, RED GIANT STARS
DOI:		10.1086/168108
Bibliographic Code:		1989ApJ...347..186A

Abstract

The oxygen abundance has been determined by analysis of the O I infrared triplet in 30 unevolved field stars of metallicities in the range Fe/H abundance ratio between -0.2 and -3.5. The data show that the O/Fe abundance ratio increases monotonically as metallicity decreases from solar, reaching values in the range 1.0-1.2 at an Fe/H abundance ratio of about -2. The results, when compared with those already published for metal-deficient red giants, suggest that oxygen could have been depleted in the latter. A discussion of the O/Fe abundance ratios in connection with the chemical evolution of the Galaxy is also presented.

Title:		Oxygen abundances in old disc and halo stars of the Galaxy
Authors:		Rebolo, R.; Abia, C.
Affiliation:		AA(Instituto de Astrofisica de Canarias, La Laguna, Spain), AB(Instituto de Astrofisica de Canarias, La Laguna, Spain)
Publication:		(Instituto de Astrofisica de Canarias and Comision Interministerial de Ciencia y Tecnologia, Summer School on Evolutionary Phenomena in Galaxies, Puerto de la Cruz, Spain, July 4-15, 1988) Astrophysics and Space Science (ISSN 0004-640X), vol. 157, no. 1-2, July 1989, p. 55-60. (Ap&SS Homepage)
Publication Date:		07/1989
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		ABUNDANCE, ACCRETION DISKS, LATE STARS, OXYGEN, STELLAR SPECTRA, CHEMICAL EVOLUTION, MILKY WAY GALAXY, STELLAR COMPOSITION
DOI:		10.1007/BF00637310
Bibliographic Code:		1989Ap&SS.157...55R

Abstract

Intermediate resolution CCD spectra of the oxygen triplet at 7770 A have been analyzed to determine oxygen abundances in a sample of metal-deficient stars with metallicities covering the range of Fe/H values between -0.2 and -2.5. Important oxygen overabundances (O/F values of not less than 1) are found in the more metal deficient stars of the sample. The information that these observations provide about the early nucleosynthesis history and chemical evolution of the Galaxy is briefly discussed.

Title:		Be-9 abundances in dwarfs of intermediate metal deficiency - Implications for galactic evolution
Authors:		Beckman, J. E.; Abia, C.; Rebolo, R.
Affiliation:		AA(Instituto de Astrofisica de Canarias, La Laguna, Spain), AB(Instituto de Astrofisica de Canarias, La Laguna, Spain), AC(Instituto de Astrofisica de Canarias, La Laguna, Spain)
Publication:		(Instituto de Astrofisica de Canarias and Comision Interministerial de Ciencia y Tecnologia, Summer School on Evolutionary Phenomena in Galaxies, Puerto de la Cruz, Spain, July 4-15, 1988) Astrophysics and Space Science (ISSN 0004-640X), vol. 157, no. 1-2, July 1989, p. 41-46. (Ap&SS Homepage)
Publication Date:		07/1989
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		BERYLLIUM 9, DWARF STARS, GALACTIC EVOLUTION, METALLICITY, ABUNDANCE, CHEMICAL EVOLUTION
DOI:		10.1007/BF00637308
Bibliographic Code:		1989Ap&SS.157...41B

Abstract

This paper presents observations of the 3130 A Be II resonance doublet in stars of intermediate metal deficiency, with Fe/H values between -0.6 and -1.1, obtained with the Intermediate Dispersion Spectrographs and IPCS detector at the 2.5 m Isaac Newton Telescope on La Palma. The derived beryllium abundances range from 5.6 x 10 to the -12th (one half solar) to 2 x 10 to the -12th (one sixth solar). These values, interpolated between the sets of previous beryllium measurements at higher and at lower metallicities, serve to confirm the monotonic variation of the Be abundance with Fe during the evolution of the galactic disk. It is found that there was no extreme burst of Be production in the halo. To circumvent the effects of depletion, a statistical set of data is needed, for which the upper envelope can be used to trace galactic Be evolution. It is noted that no observations with sufficient sensitivity to detect Be in the extremely metal deficient stars of the halo have been reported to date.

Title:		Supernovae 1989A, 1989B, 1989D
Authors:		Ruiz-Lapuente, P.; Lopez, R.; Canal, R.; Abia, C.; Cepa, J.
Publication:		IAU Circ., 4760, 1 (1989). Edited by Green, D. W. E. (IAUC Homepage)
Publication Date:		03/1989
Origin:		CBAT
Objects:		1989A; 1989B; 1989D
Bibliographic Code:		1989IAUC.4760....1R

Abstract

IAUC 4760 available at Central Bureau for Astronomical Telegrams. IAUC 4760 available at Central Bureau for Astronomical Telegrams.

Title:		Abundances of light metals and NI in a sample of disc stars
Authors:		Abia, C.; Rebolo, R.; Beckman, J. E.; Crivellari, L.
Affiliation:		AA(Instituto de Astrofisica de Canarias, La Laguna, Spain), AB(Instituto de Astrofisica de Canarias, La Laguna, Spain), AC(Instituto de Astrofisica de Canarias, La Laguna, Spain), AD(Osservatorio Astronomico, Trieste, Italy)
Publication:		Astronomy and Astrophysics (ISSN 0004-6361), vol. 206, no. 1, Nov. 1988, p. 100-107. Research supported by the Consejo Superior de Investigaciones Cientificas and CNR. (A&A Homepage)
Publication Date:		11/1988
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		GALACTIC EVOLUTION, LATE STARS, NICKEL, STELLAR COMPOSITION, IRON, METALLICITY, STELLAR ATMOSPHERES, STELLAR SPECTRA
Bibliographic Code:		1988A&A...206..100A

Abstract

High resolution, high S/N spectra obtained using RETICON and CCD detectors are used to determine the abundances of Al, Si, Ca, Ni and Fe in 23 disc stars in the metallicity range -1.2 ⪉ [Fe/H] ⪉ +0.3. The authors have found overabundances, with respect to iron for Al (≡0.4), Si (≡0.3), and Ca (≡0.2) in stars between -1.2 ⪉ [Fe/H] ⪉ -0.5. The results for Ca and Si (α-elements) are in excellent agreement with previous observational studies. The Al overabundances reported here show somewhat larger values close to [Fe/H] = -1.0 than those previously found in the literature. The abundance of Ni seems to follow that of Fe over the whole metallicity range studied.

Title:		Abundances of Be-9 in a sample of highly metal-deficient dwarfs - Implications for early galactic nucleosynthesis and primordial lithium
Authors:		Rebolo, R.; Abia, C.; Beckman, J. E.; Molaro, P.
Affiliation:		AA(Consejo Superior de Investigaciones Cientificas, Instituto de Astrofisica de Canarias, La Laguna, Spain), AB(Consejo Superior de Investigaciones Cientificas, Instituto de Astrofisica de Canarias, La Laguna, Spain), AC(Consejo Superior de Investigaciones Cientificas, Instituto de Astrofisica de Canarias, La Laguna, Spain), AD(Osservatorio Astronomico, Trieste, Italy)
Publication:		Astronomy and Astrophysics (ISSN 0004-6361), vol. 193, no. 1-2, March 1988, p. 193-201. (A&A Homepage)
Publication Date:		03/1988
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		ABUNDANCE, BERYLLIUM 9, DWARF STARS, GALACTIC EVOLUTION, LITHIUM ISOTOPES, NUCLEAR FUSION, METALLICITY, SIGNAL TO NOISE RATIOS, SPECTRUM ANALYSIS, STELLAR SPECTRA
Bibliographic Code:		1988A&A...193..193R

Abstract

Title:		Supernova 1988A in M58
Authors:		Kidger, M.; Smith, N.; Wallis, R.; Manteiga, M.; Pickles, A.; Laing, R.; Wall, J.; Canal, R.; Lopez, R.; Abia, C.; Riera, A.
Publication:		IAU Circ., 4541, 1 (1988). Edited by Green, D. W. E. (IAUC Homepage)
Publication Date:		02/1988
Origin:		CBAT
Objects:		1988A
Bibliographic Code:		1988IAUC.4541....1K

Abstract

IAUC 4541 available at Central Bureau for Astronomical Telegrams. IAUC 4541 available at Central Bureau for Astronomical Telegrams.

Title:		Galactic evolution of the light-element isotopes
Authors:		Abia, C.; Canal, R.
Affiliation:		AA(Consejo Superior de Investigaciones Cientificas, Instituto de Astrofisica de Canarias, La Laguna, Spain), AB(Barcelona, Universidad, Spain)
Publication:		Astronomy and Astrophysics (ISSN 0004-6361), vol. 189, no. 1-2, Jan. 1988, p. 55-58. (A&A Homepage)
Publication Date:		01/1988
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		GALACTIC EVOLUTION, ISOTOPIC ENRICHMENT, LIGHT ELEMENTS, LITHIUM ISOTOPES, OPHIUCHI CLOUDS, ASTRONOMICAL MODELS, GALACTIC COSMIC RAYS, NOVAE, NUCLEAR FUSION, RED GIANT STARS, TIME DEPENDENCE
Bibliographic Code:		1988A&A...189...55A

Abstract

The galactic evolution of the abundances of the light-element isotopes (⁶Li, ⁷Li, ⁹Be, ¹⁰B, and ¹¹B) is re-examined in view of recent measurements of the ⁷Li/⁶Li interstellar isotopic ratio. The high value of this ratio (≡40), found by Ferlet and Dennefeld (1984) towards ζ Oph, can be reproduced by simultaneously including contributions to the nucleosynthesis of ⁷Li by galactic cosmic rays, red giants, and novae. Good agreement with the observed abundances and isotopic ratios is also obtained for the other elements. The results show that low-energy cosmic rays should play only a minor role in galactic Li Be B production, and also that a pregalactic abundance of Li/H ≡ 10^-9 does not present a good fit to present-day values as well as to Solar-System ones.

Title:		Abundances of Light Metals in Field Stars with Metallicity Range - 1.2< [Fe/H]< + 0.3
Authors:		Abia, C.; Rebolo, R.; Beckman, J. E.; Crivellari, L.; Vila, B.
Publication:		The Impact of Very High S/N Spectroscopy on Stellar Physics: Proceedings of the 132nd Symposium of the International Astronomical Union held in Paris, France, June 29-July 3, 1987. Edited by G. Cayrel de Strobel and Monique Spite. International Astronomical Union. Symposium no. 132, Kluwer Academic Publishers, Dordrecht., p.421
Publication Date:		00/1988
Origin:		ADS
Bibliographic Code:		1988IAUS..132..421A

Abstract

High resolution, high S:N spectra are used to determine the abundances of Fe, Ni, Ca, Al and Si in 25 field dwarfs with -1.2 < [Fe/H] < +0.3. The authors find overabundances for Al, Ca and Si in stars with -1.2 < [Fe/H] < -0.5 and solar [Ni/Fe] over the whole studied range.

Title:		Be-9 abundances in halo dwarfs - Implications for early nucleosynthesis of light elements
Authors:		Abia, C.; Rebolo, R.; Beckman, J.; Molaro, P.
Affiliation:		AA(Consejo Superior de Investigaciones Cientificas, Instituto de Astrofisica de Canarias, Tenerife, Spain), AB(Consejo Superior de Investigaciones Cientificas, Instituto de Astrofisica de Canarias, Tenerife, Spain), AC(Consejo Superior de Investigaciones Cientificas, Instituto de Astrofisica de Canarias, Tenerife, Spain), AD(Trieste, Osservatorio Astronomico, Italy)
Publication:		IN: ESO Workshop on Stellar Evolution and Dynamics in the Outer Halo of the Galaxy, Garching, Federal Republic of Germany, Apr. 7-9, 1987, Proceedings (A88-38229 15-90). Garching, Federal Republic of Germany, European Southern Observatory, 1987, p. 165-171.
Publication Date:		00/1987
Category:		Astrophysics
Origin:		STI
NASA/STI Keywords:		ABUNDANCE, BERYLLIUM, DWARF STARS, HALOS, NUCLEAR FUSION, STELLAR MODELS, COSMOCHEMISTRY, FINE STRUCTURE, METALLICITY, STELLAR SPECTRA
Bibliographic Code:		1987ESOC...27..165A

Abstract

Not Available

Title:		AMICA: the NIR/MIR camera for automatic astronomical observations from Dome C, Antarctica
Authors:		Dolci, M.; Straniero, O.; di Rico, G.; Valentini, G.; Riva, A.; di Cianno, A.; Ragni, M.; Giuliani, C.; Valentini, A.; Bortoletto, F.; D'Alessandro, M.; Magrin, D.; Bonoli, C.; Fantinel, D.; Corcione, L.; Abia, C. A.; Busso, M.; Tosti, G.
Affiliation:		AA(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AB(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AC(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AD(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AE(INAF, Osservatorio Astronomico di Torino (Italy)), AF(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AG(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AH(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AI(INAF, Osservatorio Astronomico di Collurania-Teramo (Italy)), AJ(INAF, Osservatorio Astronomico di Padova (Italy)), AK(INAF, Osservatorio Astronomico di Padova (Italy)), AL(INAF, Osservatorio Astronomico di Padova (Italy)), AM(INAF, Osservatorio Astronomico di Padova (Italy)), AN(INAF, Osservatorio Astronomico di Padova (Italy)), AO(INAF, Osservatorio Astronomico di Torino (Italy)), AP(Univ. de Granada (Spain)), AQ(Univ. degli Studi di Perugia (Italy)), AR(Univ. degli Studi di Perugia (Italy))
Publication:		Ground-based and Airborne Instrumentation for Astronomy III. Edited by McLean, Ian S.; Ramsay, Suzanne K.; Takami, Hideki. Proceedings of the SPIE, Volume 7735, pp. 77353L-77353L-12 (2010). (SPIE Homepage)
Publication Date:		07/2010
Origin:		AIP
Abstract Copyright:		(c) 2010: American Institute of Physics
DOI:		10.1117/12.857192
Bibliographic Code:		2010SPIE.7735E.121D