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Asymptotic giant branch (AGB) stars play a significant role in our understanding of the origin of the elements. They contribute to the abundances of C, N, and approximately $50\%$ of the abundances of the elements heavier than iron. An…

Solar and Stellar Astrophysics · Physics 2024-12-03 Zara Osborn , Amanda I. Karakas , Alex J. Kemp , Robert Izzard , Devika Kamath , Maria Lugaro

The Post Asymptotic Giant Branch (AGB) phase is arguably one of the least understood phases of the evolution of low- and intermediate- mass stars. The two grids of models presently available are based on outdated micro- and macro-physics…

Solar and Stellar Astrophysics · Physics 2016-03-16 Marcelo M. Miller Bertolami

Asymptotic Giant Branch (AGB) stars are important players in the chemical evolution modelling of galaxies, because they are major producers of several chemical elements and excellent tracers of the structure and of the star formation…

Astrophysics · Physics 2007-05-23 Monica Tosi

We compute the evolution of the abundances of barium and europium in the Milky Way and we compare our results with the observed abundances from the recent UVES Large Program "First Stars". We use a chemical evolution model which already…

Astrophysics · Physics 2007-05-23 G. Cescutti , P. Francois , F. Matteucci , R. Cayrel , M. Spite

The Thermally-Pulsating Asymptotic Giant Branch (TP-AGB) phase of stellar evolution has received attention only recently in galaxy evolution, but is now an important player in our understanding of how galaxies form and evolve. Because it is…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-04 Claudia Maraston

Binary post-asymptotic giant branch (post-AGB) stars are thought to be the products of a strong but poorly-understood interaction during the AGB phase. The aim of this contribution is to update the orbital elements of a sample of galactic…

Solar and Stellar Astrophysics · Physics 2018-12-05 Glenn-Michael Oomen , Hans Van Winckel , Onno Pols , Gijs Nelemans , Ana Escorza , Rajeev Manick , Devika Kamath , Christoffel Waelkens

We used models of thermally-pulsing asymptotic giant branch (AGB) stars, that also describe the dust-formation process in the wind, to interpret the combination of near- and mid-infrared photometric data of the dwarf galaxy IC 1613. This is…

Solar and Stellar Astrophysics · Physics 2016-06-08 F. Dell'Agli , M. Di Criscienzo , M. L. Boyer , D. A. Garcia-Hernandez

A review is presented of the most relevant results obtained in the last few years on this rare class of astronomical sources. Multi-wavelength analysis of an increasing number of post-AGB stars reveal that they constitute a more…

Astrophysics · Physics 2009-11-11 P. Garcia-Lario

J-type stars are a subclass of carbon stars that are generally Li-rich, not enriched in s-elements, and have low $^{12}$C/$^{13}$C ratios. They were suggested to be the manufacturers of the pre-solar grains of type AB2 (having low…

Solar and Stellar Astrophysics · Physics 2024-10-17 A. Choplin , L. Siess , S. Goriely

Recent improvements in globular cluster colour-magnitude diagrams, coupled with an increase in large-sample spectroscopic abundance studies of cluster giants, finally allow some attempts at a statistically meaningful comparison of the…

Astrophysics · Physics 2007-05-23 Christopher Sneden , Inese I. Ivans , Robert P. Kraft

Around half of the heavy elements in the universe are formed through the slow neutron capture (s-) process, which takes place in thermally pulsing asymptotic giant branch (AGB) stars with masses $1-6\;M_{\odot}$. The nucleosynthetic imprint…

Solar and Stellar Astrophysics · Physics 2024-11-06 A. J. Dimoff , C. J. Hansen , R. J. Stancliffe , B. Kubatova , I. Stateva , A. Kucinskas , V. Dobrovolskas

We present dust yields for asymptotic giant branch (AGB) and super--asymptotic giant branch (SAGB) stars of solar metallicity. Stars with initial mass $1.5~M_{\odot} \leq M_{\rm ini} \leq 3~M_{\odot}$ reach the carbon star stage during the…

Solar and Stellar Astrophysics · Physics 2017-07-26 F. Dell'Agli , D. A. García-Hernádez , R. Schneider , P. Ventura , F. La Franca , R. Valiante , E. Marini , M. Di Criscienzo

We present barium, carbon, and silicon isotopic compositions of 38 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing is highly effective in removing barium contamination. Strong…

High-resolution spectroscopic observations of a hundred metal-poor Carbon and s-rich stars (CEMP-s) collected from the literature are compared with the theoretical nucleosynthesis models of asymptotic giant branch (AGB) presented in Paper I…

Solar and Stellar Astrophysics · Physics 2015-05-30 S. Bisterzo , R. Gallino , O. Straniero , S. Cristallo , F. Kaeppeler

Post-AGB stars are key objects for the study of the dramatic morphological changes of low- to intermediate-mass stars on their evolution from the Asymptotic Giant Branch (AGB) towards the Planetary Nebula stage. There is growing evidences…

We present asymptotic giant branch (AGB) models of metallicity $Z=10^{-4}$ and $Z=3\times 10^{-4}$, with the aim of understanding how the gas enrichment and the dust production change in very metal-poor environments and to assess the…

Solar and Stellar Astrophysics · Physics 2019-05-08 F. Dell'Agli , R. Valiante , D. Kamath , P. Ventura , D. A. García-Hernández

Bulk meteoritic data show isotopic variability of $slow$-neutron-capture ($s$-process) origin in a several elements heavier than Fe. One peculiar feature is that the lighter $s$-process elements (e.g., Zr and Mo) present larger anomalies…

A large sample of carbon enhanced metal-poor stars enriched in s-process elements (CEMP-s) have been observed in the Galactic halo. These stars of low mass (M ~ 0.9 Msun) are located on the main-sequence or the red giant phase, and do not…

Solar and Stellar Astrophysics · Physics 2015-05-18 S. Bisterzo , R. Gallino , O. Straniero , S. Cristallo , F. Kaeppeler

The hydrogen-deficiency in extremely hot post-AGB stars of spectral class PG1159 is probably caused by a (very) late helium-shell flash or a AGB final thermal pulse that consumes the hydrogen envelope, exposing the usually-hidden intershell…

Astrophysics · Physics 2007-05-23 K. Werner , D. Jahn , T. Rauch , E. Reiff , F. Herwig , J. W. Kruk

Context: The environmental conditions for asympotic giant branch (AGB) stars to reach the carbon-rich (C-rich) phase are important to understand the evolutionary process of AGB stars. The difference between the spatial distributions of…

Astrophysics of Galaxies · Physics 2015-05-30 Daisuke Ishihara , Hidehiro Kaneda , Takashi Onaka , Yoshifusa Ita , Mikako Matsuura , Noriyuki Matsunaga