The tale of the tail - disentangling the high transverse velocity stars in Gaia DR2 | |
Amarante, Joao A. S.1; Smith, Martin C.1; Boeche, Corrado2 | |
刊名 | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY |
2020-03-01 | |
卷号 | 492期号:3页码:3816-3828 |
关键词 | Galaxy: disc Galaxy: halo Galaxy: kinematics and dynamics |
ISSN号 | 0035-8711 |
DOI | 10.1093/mnras/staa077 |
英文摘要 | Although the stellar halo accounts for just similar to 1 per cent of the total stellar mass of the Milky Way, the kinematics of halo stars encode valuable information about the origins and evolution of our Galaxy. It has been shown that the high transverse velocity stars in Gaia DR2 reveal a double sequence in the Hertzsprung-Russell (HR) diagram, indicating a bifurcation in the local stellar halo within 1 kpc. We fit these stars by updating the popular-Besancon/Galaxia model, incorporating the latest observational results for the stellar halo and an improved kinematic description for the thick disc from Schonrich & Binney (2012). We are able to obtain a good match to the Gaia data and provide new constraints on the properties of the Galactic disc and stellar halo. In particular, we show that the kinematically defined thick-disc contribution to this high velocity tail is approximate to 13 per cent. We look in greater detail using chemistry from LAMOST DR5, identifying a population of retrograde stars with thick-disc chemistry. Our thick-disc kinematic model cannot account for this population and so we conclude there is likely to be a contribution from heated or accreted stars in the Solar Neighbourhood. We also investigate proposed dynamical substructures in this sample, concluding that they are probably due to resonant orbits rather than accreted populations. Finally, we provide new insights on the nature of the two sequences and their relation with past accretion events and the primordial Galactic disc. |
资助项目 | National Key Basic Research and Development Program of China[2018YFA0404501] ; NSFC[11673083] ; The World Academy of Sciences ; Chinese Academy of Sciences |
WOS关键词 | MILKY-WAY TOMOGRAPHY ; STELLAR HALO ; PHASE-SPACE ; DISC ; THICK ; GALAXY ; KINEMATICS ; POPULATIONS ; DISTANCES ; ORIGIN |
WOS研究方向 | Astronomy & Astrophysics |
语种 | 英语 |
出版者 | OXFORD UNIV PRESS |
WOS记录号 | WOS:000518143200054 |
资助机构 | National Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Key Basic Research and Development Program of China ; National Key Basic Research and Development Program of China ; NSFC ; NSFC ; The World Academy of Sciences ; The World Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences |
内容类型 | 期刊论文 |
源URL | [http://ir.bao.ac.cn/handle/114a11/54498] |
专题 | 中国科学院国家天文台 |
通讯作者 | Amarante, Joao A. S. |
作者单位 | 1.Chinese Acad Sci, Key Lab Res Galaxies & Cosmol, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China 2.INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy |
推荐引用方式 GB/T 7714 | Amarante, Joao A. S.,Smith, Martin C.,Boeche, Corrado. The tale of the tail - disentangling the high transverse velocity stars in Gaia DR2[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2020,492(3):3816-3828. |
APA | Amarante, Joao A. S.,Smith, Martin C.,&Boeche, Corrado.(2020).The tale of the tail - disentangling the high transverse velocity stars in Gaia DR2.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,492(3),3816-3828. |
MLA | Amarante, Joao A. S.,et al."The tale of the tail - disentangling the high transverse velocity stars in Gaia DR2".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 492.3(2020):3816-3828. |
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