Related papers: The nuclear processes responsible for the CNO synt…
Recent studies of spectral lines of the CNO elements in the Sun and unevolved disk and halo stars show that most published abundance data may be affected by systematic errors due to inadequate 1D modelling of stellar atmospheres. This…
Despite much effort in the past decades, the C-burning reaction rate is uncertain by several orders of magnitude, and the relative strength between the different channels 12C(12C,alpha)20Ne, 12C(12C,p)23Na and 12C(12C,n)23Mg is poorly…
Calculations that demonstrate the influence of three key nuclear reaction rates on the evolution of Asymptotic Giant Branch stars have been carried out. We study the case of a star with an initial mass of 2Msun and a metallicity of Z=0.01,…
Carbon-enhanced metal-poor (CEMP) r/s-stars show surface-abundance distributions characteristic of the so-called intermediate neutron capture process (i-process) of nucleosynthesis. We previously showed that the ingestion of protons in the…
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,…
We study the dependence of the CNO nuclear reaction rates on temperature, in the range of $10^7\div 10^8$ K, the typical range of temperature evolution from a Sun-like star towards a white dwarf. We show that the temperature dependence of…
Nucleosynthesis beyond Fe poses additional challenges not encountered when studying astrophysical processes involving light nuclei. Generally higher temperatures and nuclear level densities lead to stronger contributions of transitions on…
The nuclear rates for reactions involving 12C and 16O are key to compute the energy release and nucleosynthesis of massive stars during their evolution. These rates shape the stellar structure and evolution, and impact the nature of the…
We study the role played both by novae and single stars in enriching the ISM of the Galaxy with CNO group nuclei, in the framework of a detailed successful model for the chemical evolution of both the Galactic halo and disc. Once all the…
Explosive nuclear burning in astrophysical environments produces unstable nuclei which again can be targets for subsequent reactions. In addition, it involves a large number of stable nuclides which are not fully explored by experiments,…
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…
The majority of nuclear reactions in astrophysics involve unstable nuclei which are not fully accessible by experiments yet. Therefore, there is high demand for reliable predictions of cross sections and reaction rates by theoretical means.…
The propagation of uncertainties in reaction cross sections and rates of neutron-, proton-, and alpha-induced reactions into the final isotopic abundances obtained in nucleosynthesis models is an important issue in studies of…
We study the sensitivity of presupernova evolution and supernova nucleosynthesis yields of massive stars to variations of the helium-burning reaction rates within the range of their uncertainties. We use the current solar abundances from…
We investigate effects of triple-$\alpha$ and $^{12}\rm C(\alpha,\gamma) ^{16}O$ reaction rates on the production of supernova yields for a massive star of 25 $M_{\odot}$. We combine the reaction rates to examine the rate dependence, where…
Atomic data are an important source of systematic uncertainty in our determinations of nebular chemical abundances. However, we do not have good estimates of these uncertainties since it is very difficult to assess the accuracy of the…
Background: The ($\alpha$,n) and ($\alpha$,$\gamma$) reactions on $^{17,18}$O have significant impact on the neutron balance in the astrophysical $s$-process. In this scenario stellar reaction rates are required for relatively low…
New simulations demonstrate that low-mode, nonradial hydrodynamic instabilities of the accretion shock help starting hot-bubble convection in supernovae and thus support explosions by the neutrino-heating mechanism. The prevailing…
We investigate the impacts of nuclear burning on the spherically symmetric stationary accretion flow of helium-rich matter on to compact objects. We have already shown the existence of the critical accretion rates for the accretion of…
The main s-process taking place in low mass stars produces about half of the elements heavier than iron. It is therefore very important to determine the importance and impact of nuclear physics uncertainties on this process. We have…