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We describe our first attempt at modelling nucleosynthesis in massive AGB stars which have undergone core carbon burning, the super-AGB stars. We fit a synthetic model to detailed stellar evolution models in the mass range 9<=M/Msun<=11.5…

Astrophysics · Physics 2007-05-23 Robert G. Izzard , Arend Jan T. Poelarends

In past decades a lot of progress has been made towards understanding the main s-process component that takes place in thermally pulsing Asymptotic Giant Branch (AGB) stars. During this process about half of the heavy elements, mainly…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 M. Heil , A. Juseviciute , F. Kaeppeler , R. Gallino , M. Pignatari , E. Uberseder

We explore modifications to the current scenario for the slow neutron capture process in asymptotic giant branch (AGB) stars to account for the Pb deficiency observed in post-AGB stars of low metallicity ([Fe/H] ~ -1.2) and low initial mass…

Solar and Stellar Astrophysics · Physics 2015-11-04 M. Lugaro , S. W. Campbell , H. Van Winckel , K. De Smedt , A. I. Karakas , F. Käppeler

The recently improved information on the stellar neutron capture cross sections of neutron magic nuclei at N = 82, and in particular for 142^Nd, turned out to represent a sensitive test for models of s-process nucleosynthesis. While these…

Astrophysics · Physics 2007-05-23 C. Arlandini , F. Kaeppeler , K. Wisshak , R. Gallino , M. Lugaro , M. Busso , O. Straniero

The 13C(a, n)16O reaction is the major neutron source in low mass asymptotic giant branch (AGB) stars, where the main and the strong s process components are synthesised. After a third dredge-up (TDU) episode, 13C burns radiatively in a…

Solar and Stellar Astrophysics · Physics 2010-05-18 S. Bisterzo , S. Cristallo

We compare updated Torino postprocessing asymptotic giant branch (AGB) nucleosynthesis model calculations with isotopic compositions of mainstream SiC dust grains from low-mass AGB stars. Based on the data-model comparison, we provide new…

Solar and Stellar Astrophysics · Physics 2018-10-10 Nan Liu , Roberto Gallino , Sergio Cristallo , Sara Bisterzo , Andrew M. Davis , Reto Trappitsch , Larry R. Nittler

The slow neutron capture process in massive stars (the weak s-process) produces most of the s-only isotopes in the mass region 60 < A < 90. The nuclear reaction rates used in simulations of this process have a profound effect on the final…

Solar and Stellar Astrophysics · Physics 2015-05-18 M E Bennett , R Hirschi , M Pignatari , S Diehl , C Fryer , F Herwig , A Hungerford , G Magkotsios , G Rockefeller , F Timmes , M Wiescher , P Young

This review concentrates on the two principle methods used to evolve nuclear abundances within astrophysical simulations, evolution via rate equations and via equilibria. Because in general the rate equations in nucleosynthetic applications…

Astrophysics · Physics 2007-05-23 W. R. Hix , F. -K. Thielemann

A critical issue in the asymptotic giant branch (AGB) self-enrichment scenario for the formation of multiple populations in Globular Clusters (GCs) is the inability to reproduce the magnesium isotopic ratios, despite the model in principle…

Solar and Stellar Astrophysics · Physics 2018-03-28 Paolo Ventura , Franca D'Antona , Gianluca Imbriani , Marcella Di Criscienzo , Flavia Dell'Agli , Marco Tailo

We present Nested Sampling with Slice-within-Gibbs (NS-SwiG), an algorithm for Bayesian inference and evidence estimation in high-dimensional models whose likelihood admits a factorization, such as hierarchical Bayesian models. We construct…

Computation · Statistics 2026-02-20 David Yallup

A major source of uncertainty in AGB models is the partial-mixing process of hydrogen, required for the formation of the so-called $^{13}$C pocket. Among the attempts to derive a self-consistent treatment of this physical process, there are…

Solar and Stellar Astrophysics · Physics 2020-10-27 Diego Vescovi , Sergio Cristallo

For the present analysis we simulate the reaction 129Xe 54+197Au79 at E=50 MeV/nucleon respectively[3]. This reaction is simulated at different impact parameters using hard equation of state. The stored phase space is then analyzed by using…

Nuclear Theory · Physics 2011-12-23 Ekta , Suneel Kumar , Rajeev K. Puri

We construct a data base of 125 post-AGB objects (including R CrB and extreme helium stars) with published photospheric parameters (effective temperature and gravity) and chemical composition. We estimate the masses of the post-AGB stars by…

Astrophysics · Physics 2009-11-11 G. Stasinska , R. Szczerba , M. Schmidt , N. Siodmiak

We present new rates for the 22Ne(alpha, n)25Mg and 22Ne(alpha,gamma)26Mg reactions, with uncertainties that have been considerably reduced compared to previous estimates, and we study how these new rates affect the production of the heavy…

Astrophysics · Physics 2011-07-19 A. Karakas , M. Lugaro , M. Wiescher , J. Goerres , C. Ugalde

Graph Neural Networks (GNNs) have shown remarkable success in molecular tasks, yet their interpretability remains challenging. Traditional model-level explanation methods like XGNN and GNNInterpreter often fail to identify valid…

Machine Learning · Computer Science 2025-04-25 Zhaoning Yu , Hongyang Gao

One of the main challenges in modeling massive stars to the onset of core collapse is the computational bottleneck of nucleosynthesis during advanced burning stages. The number of isotopes formed requires solving a large set of…

The low-metallicity RV Tauri star MACHO47.2496.8, recently discovered in the Large Magellanic Cloud, is highly enriched in carbon and heavy elements produced by the slow neutron capture process (s-process), and is most probably a genuine…

Astrophysics · Physics 2009-11-13 A. Bonacic Marinovic , M. Lugaro , M. Reyniers , H. Van Winckel

We apply the capabilities of machine learning (ML) to discern patterns in order to classify metal-poor stars. To do so, we train an ML model on a bank of nucleosynthesis calculations derived from hydrodynamic simulations for events such as…

We discuss the synthesis of some short-lived isotopes and of 23Na in thermally pulsing AGB stars with initial mass of 2 Msun and two different metallicities (Z=1.5e-2, corresponding to the metal amount in the Sun, and Z=1e-4),…

Astrophysics · Physics 2007-05-23 S. Cristallo , R. Gallino , O. Straniero , L. Piersanti , I. Dominguez

We present a comprehensive study of s-process nucleosynthesis in 15, 20, 25, and 30 $\msun$ stellar models having solar-like initial composition. The stars are evolved up to ignition of central neon with a 659 species network coupled to the…

Astrophysics · Physics 2007-05-23 L. -S. The , M. F. El Eid , B. S. Meyer