Line shapes of the magnesium resonance lines in cool DZ white dwarf atmospheres
نویسندگان
چکیده
منابع مشابه
Search for Oxygen in Cool Dq White Dwarf Atmospheres
The existence of carbon in cool He white dwarf (WD) atmospheres has been known for a relatively long time[5]. The presence of carbon in these atmospheres is explained by convective dredge up of interior carbon [6]. Pelletier et al. (1986) presented the first detailed calculations of this process and showed that carbon diffuses upwards from the core into the base of the He-rich envelope where it...
متن کاملThe Pseudo-continuum Bound-free Opacity of Hydrogen and its Importance in Cool White Dwarf Atmospheres
We investigate the importance of the pseudo-continuum bound-free opacity from hydrogen atoms in the atmospheres of cool white dwarfs. This source of absorption, when calculated by the occupation probability formalism applied in the modeling of white dwarf atmospheres with Teff < 17000K, dominates all other sources of opacity at optical wavelengths. This is unrealistic and not observed. On the o...
متن کاملOn the Dissociation Equilibrium of H2 in Very Cool, Helium-Rich White Dwarf Atmospheres
We investigate the dissociation equilibrium of H2 in very cool, helium-rich white dwarf atmospheres. We present the solution of the non-ideal chemical equilibrium for the dissociation of molecular hydrogen in a medium of dense helium. We find that at the photosphere of cool white dwarfs of Teff = 4000K, the non-ideality results in an increase of the mole fraction of molecular hydrogen by up to ...
متن کاملNon-Ideal Equation of State, Refraction and Opacities in Very Cool, Helium-Rich White Dwarf Atmospheres
The atmospheres of cool, helium-rich white dwarfs constitute an exotic and poorly explored physical regime of stellar atmospheres. Under physical conditions where the temperature varies from 1000K to 10000K, the density can reach values as large as 2 g/cm, and the pressure is as high as 1 Mbar, the atmosphere is no longer an ideal gas and must be treated as a dense fluid. Helium atoms become st...
متن کاملDiscovery of a Magnetic DZ White Dwarf with Zeeman-Split Lines of Heavy Elements
A spectroscopic survey of unstudied Luyten Half Second proper motion stars has resulted in the discoveries of two new cool magnetic white dwarfs. One (LHS 2273) is a routine DA star, Teff= 6,500 K, with Zeeman-split Hα and Hβ, for which a simple model suggests a polar field strength of 18.5 MG viewed close to equator-on. However, the white dwarf LHS 2534 proves to be the first magnetic DZ showi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2018
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/201834067