相关论文: Particle diffusion in atmospheres of CP stars
Formulae suitable for computing light-induced drift (LID) acceleration and corresponding diffusional segregation of isotopes in CP star model atmospheres are given.
In stellar astrophysics, the study of the atmospheres of early-type stars plays a very special role. The atmospheres of these stars display a variety of different phenomena, such as the presence of large magnetic fields, strong surface…
A portion of the upper main-sequence stars, called chemically peculiar (CP) stars, show significant abundance anomalies mainly due to atomic diffusion of chemical elements within the stellar atmospheres of these stars. Slowly rotating CP…
Stellar occultations and transits occur when a planetary body passes in front of a star (including our Sun). For objects with an atmosphere, refraction plays an essential role to explain the drops of flux and the aureoles observed during…
Formation of anomalous isotope abundances in the atmospheres of chemically peculiar (CP) stars can be explained by light-induced drift (LID). This effect is additional to the radiative acceleration and appears due to systematic asymmetry of…
In this paper, I explore various transport processes that have a large impact of the distribution of elements inside stars and thus, on stellar evolution. A heuristic description of the physics behind equations is provided, and key…
Stellar atmospheres separate the hot and dense stellar interiors from the emptiness of space. Radiation escapes from the outermost layers of a star, carrying direct physical information. Underneath the atmosphere, the very high opacity…
Ap/Bp stars are magnetic chemically peculiar early A and late B type stars of the main sequence. They exhibit peculiar surface abundance anomalies that are thought to be the result of gravitational settling and radiative levitation. The…
We analyze diffusion equations in strongly coupled Coulomb mixtures of ions in dense stellar matter. Strong coupling of ions in the presence of gravitational forces and electric fields (induced by plasma polarization in the presence of…
Much of modern astrophysics is grounded on the observed chemical compositions of stars and the diffuse plasma that pervades the space between stars, galaxies and clusters of galaxies. X-ray and EUV spectra of the hot plasma in the outer…
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…
In recent papers convincing evidence has been presented for chemical stratification in Ap star atmospheres, and surface abundance maps have been shown to correlate with the magnetic field direction. Radiatively driven diffusion in magnetic…
Stars play a decisive role in our Universe, from its beginning throughout its complete evolution. For a thorough understanding of their properties, evolution, and physics of their outer envelopes, stellar spectra need to be analyzed by…
Context. Classical chemically peculiar stars exhibit atmospheres that are often structured by the effects of atomic diffusion. As a result of these elemental diffusion and horizontal abundance variations, photospheric temperature varies at…
The processes that disperse the products of massive stars from their birth sites play a fundamental role in determining the observed abundances. I discuss parameterizations for element dispersal and their roles in chemical evolution, with…
Each time diffusion of elements is invoked in explaining abundance anomalies in a star, this supposes implicitly that a stratification process is in progress somewhere in that star. This means also, that the element abundances can still be…
Stars in globular clusters (GCs) exhibit a peculiar chemical pattern with strong abundance variations in light elements along with a constant abundance in heavy elements. These abundance anomalies can be explained by a primordial pollution…
The abundance anomalies in chemically peculiar B-F stars are usually explained by diffusion of chemical elements in the stable atmospheres of these stars. But it is well known that Cp stars with similar temperatures and gravities show very…
We review the basic concepts, the present state of theoretical models, and the future prospects for theory and observations of pulsating stellar atmospheres. Our emphasis is on radially pulsating cool stars, which dynamic atmospheres…
Even today in our Galaxy, stars form from gas cores in a variety of environments, which may affect the properties of resulting star and planetary systems. Here we study the role of pressure, parameterized via ambient clump mass surface…