Related papers: Evolutionary implications of the new triple-alpha …
The origin of fluorine is a longstanding problem in nuclear astrophysics. It is widely recognized that Asymptotic Giant Branch (AGB) stars are among the most important contributors to the Galactic fluorine production. In general, extant…
We investigate the triple-alpha reaction at low energies, by assuming a direct process. The Coulomb potential of three $\alpha$ particles is examined carefully. The three-body continuum wave functions are generated by calculating an…
We present detailed models of low and intermediate-mass asymptotic giant branch (AGB) stars with and without the 18F(a,p)21Ne reaction included in the nuclear network, where the rate for this reaction has been recently experimentally…
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…
For stars between 0.8-8.0 solar masses, nucleosynthesis enters its final phase during the asymptotic giant branch (AGB) stage. During this evolutionary period, grain condensation occurs in the stellar atmosphere, and the star experiences…
Nuclear reactions govern major aspects of the chemical evolution od galaxies and stars. Analytic study of the reaction rates and reaction probability integrals is attempted here. Exact expressions for the reaction rates and reaction…
We propose a temperature-resolved Monte Carlo (MC) approach to identify the temperature regimes in which low-energy helium-burning reaction rates most strongly affect nucleosynthesis in very massive stars that undergo pair-instability…
We investigate the effects of plasma interactions on resonance-enhanced fusion rates in stars. Starting from basic principles we derive an expression for the fusion rate that can serve as a basis for discussion of approximation schemes. The…
The competing $^{22}$Ne($\alpha,\gamma$)$^{26}$Mg and $^{22}$Ne($\alpha,n$)$^{25}$Mg reactions control the production of neutrons for the weak $s$-process in massive and AGB stars. In both systems, the ratio between the corresponding…
In this last decade, our knowledge of evolutionary and structural properties of stars of different mass and chemical composition has significantly improved. This notwithstanding, updated stellar models are still affected by significant and,…
Fundamental differences in the prediction of reaction rates with intermediate and heavy target nuclei compared to the ones with light nuclei are discussed, with special emphasis on stellar modifications of the rates. Ground and excited…
Recent shell-model calculations of weak-interaction rates for nuclei in the mass range A = 45 - 65 have resulted in substantial revisions to the hitherto standard set of Fuller, Fowler, & Newman (FFN). In particular, key electron-capture…
40K plays a significant role in the radiogenic heating of earth-like exoplanets, which can affect the development of a habitable environment on their surfaces. The initial amount of 40K in the interior of these planets depends on the…
The reactions of relevance for stellar evolution are difficult to measure directly in the laboratory at the small astrophysical energies. In recent years indirect reaction methods have been developed and applied to extract low-energy…
We have continued our studies of the Classical Nova outburst by evolving TNRs on 1.25Msun and 1.35Msun WDs (ONeMg composition) under conditions which produce mass ejection and a rapid increase in the emitted light, by examining the effects…
The well-known astrophysical resonant reaction rate equations for an isolated narrow resonance have been reexamined. The validity of those `look reliable' assumptions used in deriving the analytic reaction rate equations has been checked,…
The pre-main-sequence evolution of low-mass stars and brown dwarfs is studied numerically starting from the formation of a protostellar/proto-brown dwarf seed and taking into account the mass accretion onto the central object during the…
The project aims to investigate most important weak interaction nuclei in the presupernova evolution of massive stars. To achieve the goal, an ensemble containing 728 nuclei in the mass range A = 1--100 was considered. We computed the mass…
We report new chemical abundances of 23 bright red giants of the globular cluster M3, based on high-resolution spectra obtained with the Keck I telescope. Combining these data with a previously-reported small sample of M3 giants obtained…
Sensitivities of nuclear reaction rates to a variation of nuclear properties are studied. Target nuclei range from proton- to neutron-dripline for 10<=Z<=83. Reactions considered are nucleon- and alpha-induced reactions mediated by the…