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Nuclear reactions drive the stellar evolution and contribute to the stellar and galactic chemicals abundances. New determinations of the nuclear reaction rates for key fusion reactions of stellar evolution are now available, paving the way…

Solar and Stellar Astrophysics · Physics 2024-08-14 T. Dumont , E. Monpribat , S. Courtin , A. Choplin , A. Bonhomme , S. Ekström , M. Heine , D. Curien , J. Nippert , G. Meynet

We investigate the effects of neutrino-nucleus interactions (the nu-process) on the production of iron-peak elements in Population III core-collapse supernovae. The nu-process and the following proton and neutron capture reactions produce…

Astrophysics · Physics 2009-11-13 Takashi Yoshida , Hideyuki Umeda , Ken'ichi Nomoto

Nuclear reaction rate ($\lambda$) is a significant factor in the process of nucleosynthesis. A multi-layer directed-weighted nuclear reaction network in which the reaction rate as the weight, and neutron, proton, $^4$He and the remainder…

Nuclear Theory · Physics 2020-10-13 H. L. Liu , D. D. Han , P. Ji , Y. G. Ma

Nucleosynthesis in evolved (RGB and AGB) low-mass stars is reviewed under the light of the reaction rates recommended in the NACRE compilation (Angulo et al. 1999). We use a parametric model of stellar nucleosynthesis to investigate the…

Astrophysics · Physics 2007-05-23 A. Palacios , F. Leroy , C. Charbonnel , M. Forestini

In the course of a systematic exploration of the uncertainties associated to the input micro- and macro-physics in the modeling of the evolution of intermediate mass stars during their Asymptotic Giant Branch (AGB) phase, we focus on the…

Astrophysics · Physics 2009-11-11 Paolo Ventura , Francesca D'Antona

We investigate the impact of the new LUNA rate for the nuclear reaction $^{22}$Ne$(p,\gamma)^{23}$Na on the chemical ejecta of intermediate-mass stars, with particular focus on the thermally-pulsing asymptotic giant branch (TP-AGB) stars…

The $^{22}$Ne(p,$\gamma$)$^{23}$Na reaction takes part in the neon-sodium cycle of hydrogen burning. This cycle affects the synthesis of the elements between $^{20}$Ne and $^{27}$Al in asymptotic giant branch stars and novae. The…

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

Recent observational advances have enabled high resolution mapping of ${^{44}}$Ti in core-collapse supernova (CCSN) remnants. Comparisons between observations and models provide stringent constraints on the CCSN mechanism. However, past…

High Energy Astrophysical Phenomena · Physics 2020-07-22 Shiv K. Subedi , Zach Meisel , Grant Merz

Recent investigations suggest that the neutrino--heated hot bubble between the nascent neutron star and the overlying stellar mantle of a type--II supernova may be the site of the r--process. In the preceding $\alpha$--process building up…

Nuclear Theory · Physics 2009-10-30 V. D. Efros , W. Balogh , H. Herndl , R. Hofinger , H. Oberhummer

The NO cycle takes place in the deepest layer of a H-burning core or shell, when the temperature exceeds T {\simeq} 30 {\cdot} 106 K. The O depletion observed in some globular cluster giant stars, always associated with a Na enhancement,…

Results from observations report a growing number of metal-poor stars showing an abundance pattern midway between the s- and r-processes. These so-called r/s-stars raise the need for an intermediate neutron capture process (i-process),…

Solar and Stellar Astrophysics · Physics 2022-06-29 A. Choplin , L. Siess , S. Goriely

We suggest that if the astrophysical site for r-process nucleosynthesis in the early Galaxy is confined to a narrow mass range of Type II supernova (SN II) progenitors, with a lower mass limit of Mms = 20 Msun, a unique feature in the…

Astrophysics · Physics 2009-10-31 Takuji Tsujimoto , Toshikazu Shigeyama , Yuzuru Yoshii

The evolution of massive stars with very low-metallicities depends critically on the amount of CNO nuclides which they produce. The $^{12}$N($p$,\,$\gamma$)$^{13}$O reaction is an important branching point in the rap-processes, which are…

Big bang nucleosynthesis (BBN) is the standard model theory for the production of the light nuclides during the early stages of the universe, taking place for a period of about 20 minutes after the big bang. Deuterium production, in…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-22 Joseph Moscoso , Rafael S. de Souza , Alain Coc , Christian Iliadis

Several different processes could be changing the density in the core of a neutron star, leading to a departure from $\beta$ equilibrium, quantified by the chemical potential difference $\delta\mu\equiv\mu_n-\mu_p-\mu_e$. The evolution of…

Astrophysics · Physics 2009-11-11 Sergio Flores-Tulian , Andreas Reisenegger

The $^{19}$F($\alpha$,p)$^{22}$Ne reaction is considered to be one of the main sources of fluorine depletion in AGB and Wolf-Rayet stars. The reaction rate still retains large uncertainties due to the lack of experimental studies available.…

Studies of nucleosynthesis in neutrino-driven winds from nascent neutron stars show that the elements from Sr through Ag with mass numbers A~88-110 are produced by charged-particle reactions (CPR) during the alpha-process in the winds.…

Astrophysics · Physics 2009-11-13 Y. -Z. Qian , G. J. Wasserburg

Slow neutron captures at A$\gtrsim$ 85 are mainly guaranteed by the reaction 13C($\alpha$,n)16O in AGB stars, requiring proton injections from the envelope. These were so far assumed to involve a small mass ($\lesssim 10^{-3}$ M$_{\odot}$),…

Solar and Stellar Astrophysics · Physics 2015-06-19 O. Trippella , M. Busso , E. Maiorca , F. Käppeler , S. Palmerini

The s-process in massive stars, producing nuclei up to $A\approx 90$, has a different behaviour at low metallicity if stellar rotation is significant. This enhanced s-process is distinct from the s-process in massive stars around solar…

Solar and Stellar Astrophysics · Physics 2018-02-19 N. Nishimura , R. Hirschi , T. Rauscher