Related papers: Heavy element diffusion and globular cluster ages
We study the structural characteristic of the variable DA white dwarf G117B-15A by applying the methods of asteroseismology. For such a purpose, we construct white dwarf evolutionary models considering a detailed and up-to-date physical…
Variations in chemical abundances with evolutionary phase have been identified among stars in globular and open clusters with a wide range of metallicities. In the metal-poor clusters, these variations compare well with predictions from…
We revisit the phenomenon of elements diffusion in the intergalactic medium (IGM) in clusters of galaxies. The diffusion is driven by gravity, concentration and temperature gradients. The latter cause thermal diffusion, which has been so…
Star cluster formation is a major mode of star formation in the extreme conditions of interacting galaxies and violent starbursts. Young clusters are observed to form in a variety of such galaxies, a substantial number resembling the…
We discuss the diffuse emission of gamma rays and neutrinos from galaxy clusters in the viable models for structure formation in the universe. We use a self-consistent picture for cluster formation and evolution starting from a primordial…
Context. Metal-poor massive stars are supposed to be progenitors of certain supernovae, gamma-ray bursts and compact object mergers, potentially contributing to the early epochs of the Universe with their strong ionizing radiation. However,…
We investigate the long-term dynamical evolution of two distinct stellar populations of low-mass stars in globular clusters in order to study whether the energy equipartition process can explain the high number of stars harbouring abundance…
We derive a new expression for the coefficient $D_{\mathrm{h}}$ of diffusion by horizontal turbulence in rotating stars. This new estimate can be up to two orders of magnitude larger than given by a previous expression. As a consequence the…
We discuss theoretical predictions concerning the evolution of globular cluster Pop.II stars vis-a-vis current estimates of standard errors in the determination of nuclear burning rates. Numerical evaluations are given for the dependence of…
Evolutionary synthesis models for star clusters of various metallicities including gaseous emission during the lifetime of the ionising stars are used to model star cluster systems comprising two populations: an old metal-poor globular…
We highlight the role of the light elements (Li, Be, B) in the evolution of massive single and binary stars, which is largely restricted to a diagnostic value, and foremost so for the element boron. However, we show that the boron surface…
Context. The benchmark open cluster M67 is known to have solar metallicity and similar age as the Sun. It thus provides us a great opportunity to study the properties of solar twins, as well as the evolution of Sun-like stars. Aims.…
We compare the observed peaked iron abundance profiles for a small sample of groups and clusters with the predictions of a simple model involving the metal ejection from the brightest galaxy and the subsequent diffusion of metals by…
The present paper reviews massive star (initial mass smaller than 120 M0) and very massive star (initial mass larger than 120 M0) evolution. I will focus on evolutionary facts and questions that may critically affect predictions of…
The presence of elements heavier than helium ("metals") is of fundamental importance for a large number of astrophysical processes occurring in planet, star and galaxy formation; it also affects cosmic structure formation and evolution in…
Globular clusters (GCs) are among the oldest objects in the Universe for which an age can be directly measured, thus playing an important cosmological role. This age, on the other hand, depends sensitively on the He abundance, which cannot…
We investigate the non-linear evolution of spherical density and velocity perturbations of dark matter and dark energy in the expanding Universe. For that we have used the conservation and Einstein equations to describe the evolution of…
The chemical feedback from stellar winds in low metallicity (Z) environments is key for understanding the evolution of globular clusters and the early Universe. With disproportionate mass lost from the most massive stars (M > 100Msun), and…
We investigate the evolutionary behavior of stellar structures with metallicity Z=0.04 in order to disclose theoretical expectations for both evolutionary and pulsational behaviors of Super-Metal-Rich (SMR) objects, which are found in the…
Element diffusion is expected to occur in all kinds of stars : according to the relative effect of gravitation and radiative acceleration, they can fall or be pushed up in the atmospheres. Helium sinks in all cases, thereby creating a…