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591 High-velocity Stars in the Galactic Halo Selected from LAMOST DR7 and Gaia DR2

文献类型:期刊论文

AuthorLi,Yin-Bi1; Luo,A-Li1,2; Lu,You-Jun1,2; Zhang,Xue-Sen3; Li,Jiao1,4; Wang,Rui1; Zuo,Fang1,2; Xiang,Maosheng5; Ting,Yuan-Sen6,7,8,9; Marchetti,Tommaso10
SourceThe Astrophysical Journal Supplement Series
Issued Date2020-12-17
Volume252Issue:1
KeywordHigh-velocity stars
ISSN0067-0049
DOI10.3847/1538-4365/abc16e
Corresponding AuthorLuo,A-Li()
English AbstractAbstract In this paper, we report 591 high-velocity star candidates (HiVelSCs) selected from over 10 million spectra of Data Release 7 (DR7) of the Large Sky Area Multi-object Fiber Spectroscopic Telescope and the second Gaia data release, with three-dimensional velocities in the Galactic rest frame larger than 445 km s?1. We show that at least 43 HiVelSCs are unbound to the Galaxy with escape probabilities larger than 50%, and this number decreases to eight if the possible parallax zero-point error is corrected. Most of these HiVelSCs are metal-poor and slightly α-enhanced inner halo stars. Only 14% of them have [Fe/H]?>??1, which may be the metal-rich “in situ” stars in the halo formed in the initial collapse of the Milky Way or metal-rich stars formed in the disk or bulge but kinematically heated. The low ratio of 14% implies that the bulk of the stellar halo was formed from the accretion and tidal disruption of satellite galaxies. In addition, HiVelSCs on retrograde orbits have slightly lower metallicities on average compared with those on prograde orbits; meanwhile, metal-poor HiVelSCs with [Fe/H]?
Language英语
PublisherThe American Astronomical Society
WOS IDIOP:0067-0049-252-1-ABC16E
源URL[http://ir.ynao.ac.cn/handle/114a53/24009]  
Collection云南天文台_大样本恒星演化研究组
Corresponding AuthorLuo,A-Li
Affiliation1.CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, People's Republic of China lal@bao.ac.cn, luyj@bao.ac.cn, gzhao@bao.ac.cn
2.School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
3.ExtantFuture (Beijing) Technology Co., Ltd, Beijing 100102, People’ Republic Of China
4.Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011, People's Republic of China
5.Max-Planck Institute for Astronomy, Konigstuhl 17, D-69117 Heidelberg, Germany
6.Institute for Advanced Study, Princeton, NJ 08540, USA
7.Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08540, USA
8.Observatories of the Carnegie Institution of Washington, 813 Santa Barbara St., Pasadena, CA 91101, USA
9.Research School of Astronomy & Astrophysics, Australian National University, Cotter Rd., Weston, ACT 2611, Australia
10.European Southern Observatory, Karl Schwarzschild-Strasse 2, 85748 Garching bei Munchen, Germany
Recommended Citation
GB/T 7714
Li,Yin-Bi,Luo,A-Li,Lu,You-Jun,et al. 591 High-velocity Stars in the Galactic Halo Selected from LAMOST DR7 and Gaia DR2[J]. The Astrophysical Journal Supplement Series,2020,252(1).
APA Li,Yin-Bi.,Luo,A-Li.,Lu,You-Jun.,Zhang,Xue-Sen.,Li,Jiao.,...&Zhao,Gang.(2020).591 High-velocity Stars in the Galactic Halo Selected from LAMOST DR7 and Gaia DR2.The Astrophysical Journal Supplement Series,252(1).
MLA Li,Yin-Bi,et al."591 High-velocity Stars in the Galactic Halo Selected from LAMOST DR7 and Gaia DR2".The Astrophysical Journal Supplement Series 252.1(2020).

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来源:云南天文台

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