The atmospheres of helium-deficient Bp stars |
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| Authors: | Yu V Glagolevskij V V Leushin G A Chuntonov D Shulyak |
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| Institution: | (1) Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz, 369467 Karachai-Cherkessia, Russia;(2) Tavrian National University, Yaltinskaya ul. 4, Simferopol, Crimea, 330000, Ukraine |
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| Abstract: | Based on spectra taken with a 6-m telescope, we analyzed the abundances of chemical elements in the He-weak stars HD 21699
and HD 217833, estimated their surface magnetic fields (Bs = 4000 and 4500 G, respectively) from the magnetic intensification of spectral lines, and determined their microturbulences
(V
t = 0.80 and 0.75 km s−1, respectively). The low values of V
t show that the stellar atmospheres are stabilized by a magnetic field, which explains the presence of diffusion processes
that lead to chemical anomalies. Helium is strongly underabundant, and its deficiency is −1.50 and −1.81 dex in HD 21699 and
HD 217833, respectively. We used model atmospheres to determine the effective temperatures, T
eff = 16 000 and 15 450 K, and surface gravities, log g = 4.15 and 3.88, for the stars from the Hδ line, implying that they lie on the main sequence near the stars of luminosity
class V. |
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