The evolution of helium-rich subdwarf-B stars

被引：9

作者：

Ahmad, A ^{[1
]}

Jeffery, CS ^{[1
]}

机构：

[1] Armagh Observ, Armagh BT61 9DG, North Ireland

来源：

ASTROPHYSICS AND SPACE SCIENCE | 2004年 / 291卷 / 3-4期

关键词：

helium-rich subdwarf-B stars; evolution; spectroscopy; physical parameters;

D O I：

10.1023/B:ASTR.0000044329.56416.c2

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Helium-rich subdwarf-B (He-sdB) stars are extremely rare hot subluminous stars found in the field of our Galaxy as well as in some globular clusters. The existence of these hot helium stars cannot be explained by canonical stellar evolution theories nor can it be explained by normal sdB evolution. We discuss the existing evolutionary models for the formation of He-sdB stars-the flash mixing model and the binary white dwarf merger model in the light of new observational results. Spectral classification of objects as He-sdB stars by various authors has resulted in a range of objects, including white dwarfs, being classified as He-sdB stars. We propose a homogeneous definition for this class of objects based on the original classification scheme used in the PG catalogue. Spectral analysis of He-sdB stars in the last 15 years is also briefly reviewed.

引用

页码：253 / 260

页数：8

共 35 条

[1] Physical parameters of helium-rich subdwarf B stars from spectral energy distributions [J].