Related papers: Modelling of mercury isotope separation in CP stel…
Atutov and Shalagin (1988) proposed light-induced drift (LID) as a physically well understandable mechanism to explain the formation of isotopic anomalies observed in CP stars. We generalized the theory of LID and applied it to diffusion of…
Formulae suitable for computing light-induced drift (LID) acceleration and corresponding diffusional segregation of isotopes in CP star model atmospheres are given.
We give concisely the formulae governing diffusion of chemical elements and their isotopes in quiescent stellar atmospheres, due to electrostatic, gravitational and radiation fields and to impacts between particles. Isotope segregation of…
I summarize the stellar side of the cosmological lithium problem(s). Evidence from independent studies is accumulating and indicates that stars may very well be fully responsible for lowering their surface lithium from the predicted…
We study lithium depletion in low-mass and solar-like stars as a function of time, using a new diffusion coefficient describing extra-mixing taking place at the bottom of a convective envelope. This new form is motivated by…
We have identified an important source of mixing in stellar radiation zones, that would arise whenever two conditions are satisfied: (1) the presence of an inverse vertical compositional gradient, and (2) the presence of…
Current observations indicate that stars with higher rotation rates appear to maintain more surface lithium, and the majority of lithium-rich giants are indeed red clump stars. Hence, we investigate the mechanisms behind lithium enrichment…
We investigate the effects of stellar limb-darkening and photospheric perturbations for the onset of wind structure arising from the strong, intrinsic line-deshadowing instability (LDI) of a line-driven stellar wind. A linear perturbation…
We present simulations of initially stable isothermal clouds exposed to ionising radiation from a discrete external source, and identify the conditions that lead to radiatively driven implosion and star formation. We use the Smoothed…
Ozak et al. [2016] claimed that explicitly including the effect of CO$_2$ collisional line mixing (LM) in their radiative transfer calculations yield CO$_2$ atmospheres that are more transparent to infrared radiation than when spectra…
The escape of LyC photons emitted by massive stars from the dense interstellar medium of galaxies is one of the most significant bottlenecks for cosmological reionization. The escape fraction shows significant scatter between galaxies, and…
Numerical computations of stellar oscillations for models representative of B-type stars predict fewer modes to be excited than observations reveal from modern space-based photometric data. One shortcoming of state-of-the-art evolution…
In the subset of luminous, early-type stars with strong, large-scale magnetic fields and moderate to rapid rotation, material from the star's radiatively driven stellar wind outflow becomes trapped by closed magnetic loops, forming a…
Lithium is an excellent tracer of mixing in stars as it is destroyed (by nuclear reactions) at a temperature around $\sim 2.5\times 10^6$ K. The lithium destruction zone is typically located in the radiative region of a star. If the…
Stellar models with masses ranging from 0.5 to $1.3~M_\odot$ were constructed in order to compare to young cluster observations of Li and of rotation velocities. The amount of Li depletion in cool stars is sensitive to the amount of…
We present simulations of initially stable isothermal clouds exposed to ionizing radiation from a discrete external source, and identify the conditions that lead to radiatively driven implosion and star formation. We use the Smoothed…
When modelling stars with masses larger than 1.2Msun with no observed chemical peculiarity, atomic diffusion is often neglected because, on its own, it causes unrealistic surface abundances compared with those observed. The reality is that…
Context: The presence of heavier chemical elements in stellar atmospheres influences the spectral energy distribution (SED) of stars. An uneven surface distribution of these elements, together with flux redistribution and stellar rotation,…
Cosmic-ray (CR) diffusion is the result of the interaction of such charged particles against magnetic fluctuations. These fluctuations originate from large-scale turbulence cascading towards smaller spatial scales, decomposed into three…
The atmospheric structure of chemically peculiar stars deviates from that of normal stars with similar fundamental parameters due to unusual chemistry, abundance inhomogeneities and the presence of strong magnetic field. These effects are…