相关论文: Impact of helium diffusion and helium-flash-induce…
Hydrogen-rich matter has been added to a CO white dwarf of initial mass 0.516 \msun at the rates $10^{-8}$ and $2\times 10^{-8}$ \msun \yrm1, and results are compared with those for a white dwarf of the same initial mass which accretes pure…
The rotation of stars has many interesting and important consequences for the photometric and chemical evolution of galaxies. Many of the predictions of models of stellar rotation are now compared with observations of surface abundances and…
For the purpose of deriving the helium abundances in chemically peculiar stars, the importance of assuming a correct helium abundance has been investigated for determining the effective temperature and gravity of main sequence B-type stars,…
To understand better the early galactic production of Li, Be, and B by cosmic ray spallation and fusion reactions, the dependence of these production rates on cosmic ray models and model parameters is examined. The sensitivity of elemental…
The observed abundance variations in globular cluster red giants indicate that these stars may be mixing helium from the hydrogen shell outward into the envelope, presumably as a result of internal rotation. We have investigated the…
We investigate the evolution of initially metal-free, low-mass Red Giant stars through the He core flash at the tip of the Red Giant Branch. The low entropy barrier between the helium- and hydrogen-rich layers enables a penetration of the…
Turbulent mixing remains one of the primary uncertainties in the modeling of stellar interiors. In stellar evolution simulations, regions where mixing occurs are typically identified using instability criteria. A particularly interesting…
Stellar models with homogeneous abundances fail to reproduce the pulsation frequencies of early B-type stars. Their oscillations are excited by kappa-mechanism involving the Fe-peak elements where they are main contributors to the opacity…
We revisit the process of gravitational sedimentation of helium and heavy elements in the intra-cluster medium. We find that helium applies an inward drag force on heavy elements, boosting their sedimentation speed to nearly half its own.…
Recent UV observations of the most massive Galactic globular clusters show a significant population of hot stars below the zero-age HB (``blue hook'' stars), which cannot be explained by canonical stellar evolution. Stars which suffer…
Shell convection driven by nuclear burning in a stellar core is a common hydrodynamic event in the evolution of many types of stars. We encounter and simulate this convection (i) in the helium core of a low-mass red giant during core helium…
We develop further the proposal of arXiv:0806.3692 that a new state of matter -- charged condensate of spin-0 nuclei -- may exist in helium-core dwarf stars. The charged condensate and its fluctuations are described by an effective field…
ZZ Ceti stars are pulsating white dwarfs with a carbon-oxygen core (or possibly ONe for the most massive stars) build up during the core helium burning (CHeB) and thermally pulsing Asymptotic Giant Branch (TP-AGB) phases. Through the…
Mode identification is crucial for an asteroseismological study of any significance. Contrarily to spectroscopic techniques, methods such as period-fitting and multi-colour photometry do not provide a full reconstruction of non-radial…
Stars between two and three solar masses rotate rapidly on the main sequence, and the detection of slow core and surface rotation in the core-helium burning phase for these stars places strong constraints on their angular momentum transport…
Understanding whether Helium can sediment to the core of galaxy clusters is important for a number of problems in cosmology and astrophysics. All current models addressing this question are one-dimensional and do not account for the fact…
In order to investigate the near wing of the Lyman-alpha line, accurate line profile calculations and molecular data are both required due to the existence of a close line satellite responsible for its asymmetrical shape. Lyman-alpha lines…
One of the least understood aspects of white dwarf evolution is the process by which they are formed. We are aided, however, by the fact that many H- and He-deficient pre-white dwarfs (PWDs) are multiperiodic g-mode pulsators. Pulsations in…
Understanding the explosion mechanism and hydrodynamic evolution of core-collapse supernovae is a long-standing quest in astronomy. The asymmetries caused by the explosion are encoded into the line profiles which appear in the nebular phase…
In the first paper of this series, we discussed analytically, in an approximate way, the mixing processes which occur in slowly rotating stars when the feed-back effects due to the diffusion-induced $\mu$-gradients are introduced in the…