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Related papers: Advances in s-process models

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Convection and mass loss by stellar winds are two dynamical processes that shape asymptotic giant branch (AGB) stars and their evolution. Observations and earlier 3D models indicate that giant convection cells cause high-contrast surface…

Solar and Stellar Astrophysics · Physics 2023-01-30 Bernd Freytag , Susanne Höfner

Understanding the nucleosynthesis and evolution of Asymptotic Giant Branch (AGB) stars is of primary importance as they are the main producers of some of the key elements in the Universe. They are the predominant sites for the slow…

Solar and Stellar Astrophysics · Physics 2020-12-15 J. Shejeelammal , Aruna Goswami

Dynamical stellar-evolution modeling through the AGB phase reveals that radial pulsations with very fast-growing amplitudes develop if the luminosity to mass ratio of stars with tenuous envelopes exceeds a critical limit. An instability…

Solar and Stellar Astrophysics · Physics 2023-03-22 Alfred Gautschy

The $s$-process in massive stars produces the weak component of the $s$-process (nuclei up to $A \sim 90$), in amounts that match solar abundances. For heavier isotopes, such as barium, production through neutron capture is significantly…

Solar and Stellar Astrophysics · Physics 2017-05-26 Nobuya Nishimura , Raphael Hirschi , Thomas Rauscher , Alexander St. J. Murphy , Gabriele Cescutti

Stars of intermediate mass (~4-8Msun) evolve to the stage of white dwarfs through the asymptotic giant branch (AGB) stage: stationary hydrogen shell burning and helium thermal pulses, wind mass loss and planetary nebula ejection. Almost the…

Solar and Stellar Astrophysics · Physics 2026-05-27 Paolo Ventura , Francesca D'Antona

We present a large set of theoretical isochrones, whose distinctive features mostly reside on the greatly improved treatment of the thermally pulsing asymptotic giant branch (TP-AGB) phase. Essentially, we have coupled the TP-AGB tracks…

Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the…

Due to thermal pulses, asymptotic giant branch (AGB) stars experience periods of convective mixing that provide ideal conditions for slow neutron-capture nucleosynthesis. These processes are affected by large uncertainties and are still not…

Solar and Stellar Astrophysics · Physics 2018-06-20 Lisa Löbling

We present the first calculations to follow the evolution of all stable isotopes (and their abundant radioactive progenitors) in a finely zoned stellar model computed from the onset of central hydrogen burning through explosion as a Type II…

Astrophysics · Physics 2007-05-23 A. Heger , R. D. Hoffman , T. Rauscher , S. E. Woosley

I discuss the recent progress in our understanding of nucleosynthesis via rapid neutron capture, the r-process, based on meteoritic data for the early solar system and observations of stars at low metallicities. At present, all data require…

Astrophysics · Physics 2009-10-31 Yong-Zhong Qian

Based on stellar evolution simulations, we demonstrate that rapidly accreting white dwarfs in close binary systems are an astrophysical site for the intermediate neutron-capture process. During recurrent and very strong He-shell flashes in…

Solar and Stellar Astrophysics · Physics 2017-01-18 Pavel Denissenkov , Falk Herwig , Umberto Battino , Christian Ritter , Marco Pignatari , Samuel Jones , Bill Paxton

In this paper we present the evolution of a low mass model (initial mass M=1.5 Msun) with a very low metal content (Z=5x10^{-5}, equivalent to [Fe/H]=-2.44). We find that, at the beginning of the AGB phase, protons are ingested from the…

Solar and Stellar Astrophysics · Physics 2015-05-13 S. Cristallo , L. Piersanti , O. Straniero , R. Gallino , I. Dominguez , F. Kappeler

Motivated by unexplained observations of low sulphur abundances in planetary nebulae (PNe) and the PG1159 class of post asymptotic giant branch (AGB) stars, we investigate the possibility that sulphur may be destroyed by nucleosynthetic…

Solar and Stellar Astrophysics · Physics 2013-06-04 Luke J. Shingles , Amanda I. Karakas

We present an evolutionary sequence of a low mass star from the Asymptotic Giant Branch (AGB) through its post-AGB stage, during which its surface chemical composition changes from hydrogen-rich to strongly hydrogen-deficient as consequence…

Astrophysics · Physics 2007-05-23 F. Herwig , T. Bloecker , N. Langer , T. Driebe

Intense mass loss through cool, low-velocity winds is a defining characteristic of low-to-intermediate mass stars during the asymptotic giant branch (AGB) evolutionary stage. Such winds return up ~80% of the initial stellar mass to the…

Solar and Stellar Astrophysics · Physics 2023-07-21 Lynn D. Matthews

Abridged. We aim to better characterise the evolution and fates, and determine updated nucleosynthetic yields of intermediate-mass stars between primordial and EMP metallicity (Z=1e-10, 1e-8, 1e-7, 1e-6 and 1e-5). We also probed…

Solar and Stellar Astrophysics · Physics 2022-12-14 P. Gil-Pons , C. L. Doherty , S. W. Campbell , J. Gutiérrez

We study the evolution of Eu and Ba abundances in local group dwarf spheroidal and ultra faint dwarf galaxies by means of detailed chemical evolution models and compare our results with new sets of homogeneous abundances. The adopted models…

We have extended our published set of low mass AGB stellar models to lower metallicity. Different mass loss rates have been explored. Interpolation formulae for luminosity, effective temperature, core mass, mass of dredge up material and…

Astrophysics · Physics 2009-11-10 Oscar Straniero , Inma Dominguez , Sergio Cristallo , Roberto Gallino

We analyze binary population models of double-neutron stars and compare results to the accurately measured orbital periods and eccentricities of the eight known such systems in our Galaxy. In contrast to past similar studies, we especially…

Solar and Stellar Astrophysics · Physics 2015-03-26 Jeff J. Andrews , Will M. Farr , Vicky Kalogera , Bart Willems

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…

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