The origin of subdwarf B stars - I. The formation channels

	The origin of subdwarf B stars - I. The formation channels
	Han ZW(韩占文)1 ; Podsiadlowski, P 2; Maxted, PFL 3; Marsh, TR 4; Ivanova, N 2,5
刊名	MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
	2002-10-21
卷号	336 期号:2 页码:449-466
关键词	methods : numerical binaries : close stars : formation subdwarfs white dwarfs
ISSN号	0035-8711
通讯作者	Han, Z (reprint author), Chinese Acad Sci, Natl Astron Observ, Yunnan Observ, POB 110, Kunming 650011, Peoples R China.
产权排序	第一完成单位
英文摘要	Subdwarf B (sdB) stars (and related sdO/sdOB stars) are believed to be helium-core-burning objects with very thin hydrogen-rich envelopes. In recent years it has become increasingly clear from observational surveys that a large fraction of these objects are members of binary systems. To understand their formation better, we present the results of a detailed investigation of the three main binary evolution channels that can lead to the formation of sdB stars: the common-envelope (CE) ejection channel, the stable Roche lobe overflow (RLOF) channel, and the double helium white dwarfs (WDs) merger channel. The CE ejection channel leads to the formation of sdB stars in short-period binaries with typical orbital periods between 0.1 and 10 d, very thin hydrogen-rich envelopes and a mass distribution sharply peaked around similar to0.46 M-.. On the other hand, under the assumption that all mass transferred is soon lost, the stable RLOF channel produces sdB stars with similar masses but long orbital periods (400-1500 d) and with rather thick hydrogen-rich envelopes. The merger channel gives rise to single sdB stars whose hydrogen-rich envelopes are extremely thin but which have a fairly wide distribution of masses (0.4-0.65 M-.). We obtained the conditions for the formation of sdB stars from each of these channels using detailed stellar and binary evolution calculations where we modelled the detailed evolution of sdB stars and carried out simplified binary population synthesis simulations. The observed period distribution of sdB stars in compact binaries strongly constrains the CE ejection parameters. The best fits to the observations are obtained for very efficient CE ejection where the envelope ionization energy is included, consistent with previous results. We also present the distribution of sdB stars in the T (eff) -log g diagram, the Hertzsprung-Russell diagram and the distribution of mass functions.
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	COMMON ENVELOPE EVOLUTION ; HORIZONTAL-BRANCH STARS ; MASS-RATIO DISTRIBUTION ; INFRARED FLUX EXCESSES ; LARGE MAGELLANIC CLOUD ; PALOMAR-GREEN SURVEY ; NEUTRINO ENERGY-LOSS ; DOUBLE WHITE-DWARFS ; STELLAR EVOLUTION ; HOT SUBDWARFS
收录类别	SCI
原文出处	http://adsabs.harvard.edu/abs/2002MNRAS.336..449H
语种	英语
WOS记录号	WOS:000178605800015
内容类型	期刊论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/4397]
专题	云南天文台_大样本恒星演化研究组
作者单位	1.Yunnan Observatory, National Astronomical Observatories, Chinese Academy of Sciences, PO Box 110, Kunming, 650011, China 2.Department of Astrophysics, University of Oxford, Oxford OX1 3RH 3.Department of Physics, Keele University, Staffordshire ST5 5BG 4.University of Southampton, Department of Physics and Astronomy, Highfield, Southampton SO17 1BJ 5.Department of Physics and Astronomy, Northwestern University, Evanston, 1L 60208, USA
推荐引用方式 GB/T 7714	Han ZW,Podsiadlowski, P,Maxted, PFL,et al. The origin of subdwarf B stars - I. The formation channels[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2002,336(2):449-466.
APA	Han ZW,Podsiadlowski, P,Maxted, PFL,Marsh, TR,&Ivanova, N.(2002).The origin of subdwarf B stars - I. The formation channels.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,336(2),449-466.
MLA	Han ZW,et al."The origin of subdwarf B stars - I. The formation channels".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 336.2(2002):449-466.