Hot Subdwarf Stars Identified in Gaia DR2 with Spectra of LAMOST DR6 and DR7. I. Single-lined Spectra

doi:10.3847/1538-4357/ab660a

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	Hot Subdwarf Stars Identified in Gaia DR2 with Spectra of LAMOST DR6 and DR7. I. Single-lined Spectra
	Lei,Zhenxin 2,3; Zhao,Jingkun 3; Németh,Péter 1,4; Zhao,Gang 3
刊名	The Astrophysical Journal
	2020-01-30
卷号	889 期号:2
关键词	Subdwarf stars Stellar classification Surveys
ISSN号	0004-637X
DOI	10.3847/1538-4357/ab660a
英文摘要	Abstract 182 single-lined hot subdwarf stars are identified by using spectra from the sixth and seventh data releases (DR6 and DR7) of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope survey. We classified all the hot subdwarf stars using a canonical classification scheme, and got 89 sdB, 37 sdOB, 26 sdO, 24 He-sdOB, 3 He-sdO, and 3 He-sdB stars, respectively. Among these stars, 108 hot subdwarfs are newly discovered, while 74 stars were reported by previous catalogs. The atmospheric parameters of these stars were obtained by fitting the hydrogen (H) and helium (He) lines with non-local thermodynamic equilibrium model atmospheres. The atmospheric parameters confirm the two He sequences and the two subgroups of He-sdOB stars in our samples, which were found by previous studies in the Teff– diagram. Our results demonstrate different origins of field hot subdwarf stars and extreme horizontal branch stars in globular clusters, and provide strict observational limits on the formation and evolution models of the different sub-types of these evolved objects. Based on the results, we evaluated the completeness of the Geier et al. catalog. We found the fraction of hot subwarf stars is between 10% and 60%, depending on the brightness of the sample. A more accurate estimation for the hot subdwarf fraction can be obtained when similar results from composite spectra will become available.
语种	英语
出版者	The American Astronomical Society
WOS记录号	IOP:0004-637X-889-2-AB660A
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/28518]
专题	中国科学院国家天文台
作者单位	1.Astronomical Institute of the Czech Academy of Sciences, CZ-251 65, Ond?ejov, Czech Republic 2.Physics Department, Xiangtan University, Xiangtan 411105, People’s Republic of China 3.Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, People’s Republic of China zxlei@nao.cas.cn, gzhao@nao.cas.cn 4.Astroserver.org, 8533 Malomsok, Hungary
推荐引用方式 GB/T 7714	Lei,Zhenxin,Zhao,Jingkun,Németh,Péter,et al. Hot Subdwarf Stars Identified in Gaia DR2 with Spectra of LAMOST DR6 and DR7. I. Single-lined Spectra[J]. The Astrophysical Journal,2020,889(2).
APA	Lei,Zhenxin,Zhao,Jingkun,Németh,Péter,&Zhao,Gang.(2020).Hot Subdwarf Stars Identified in Gaia DR2 with Spectra of LAMOST DR6 and DR7. I. Single-lined Spectra.The Astrophysical Journal,889(2).
MLA	Lei,Zhenxin,et al."Hot Subdwarf Stars Identified in Gaia DR2 with Spectra of LAMOST DR6 and DR7. I. Single-lined Spectra".The Astrophysical Journal 889.2(2020).