Three new late-type hypervelocity star candidates from Gaia DR2 with refined selection criteria  

作　　者：Jiao Li Shi Jia Yan Gao Deng-Kai Jiang Thomas Kupfer Ulrich Heber Chao Liu Xue-Fei Chen Zhan-Wen Han 

机构地区：[1]Yunnan observatories,Chinese Academy of Sciences,Kunming 650011,China [2]Key Laboratory for the Structure and Evolution of Celestial Objects,Yunnan observatories,Chinese Academy of Sciences,Kunming 650011,China [3]University of Chinese Academy of Sciences,Beijing 100049,China [4]Center for Astronomical Mega-Science,Chinese Academy of Sciences,Beijing 100101,China [5]State Key Laboratory of Lunar and Planetary Sciences,Macao University of Science and Technology,Macao,China [6]Kavli Institute for Theoretical Physics,University of California,Santa Barbara,CA 93106,USA [7]Department of Physics,University of California,Santa Barbara,CA 93106,USA [8]Dr.Remeis-Sternwarte&ECAP,University of Erlangen-Nurnberg,Erlangen,Germany [9]Key Lab of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China

出　　处：《Research in Astronomy and Astrophysics》2020年第3期170-184,共15页天文和天体物理学研究（英文版）

基　　金：Funding for the DPAC has been provided by national institutions,in particular the institutions participating in the Gaia Multilateral Agreement;supported by the Natural Natural Science Foundation of China(NSFC)(Grant Nos.11521303,11573061,11733008 and11661161016);Yunnan province(2015FB190);the Science and Technology Development Fund,Macao SAR(File Nos.001/2016/AFJ and 0001/2019/A1);supported by the NSFC(Grant Nos.11333003and 11390372).

摘　　要：Several dozen hypervelocity star(HVS)candidates have been reported based on the second data release of Gaia(Gaia DR2).However,it has been proven that the radial velocities of some Gaia HVS candidates are not reliable.In this paper,we employ refined astrometric criteria to re-examine Gaia DR2,arriving at a more reliable sample of HVS and high velocity star candidates than those found by previous authors.We develop a method called Binary Escape Probability Analysis to identify some HVS candidates.This method allows us to work with stars having only two epochs of measured radial velocity.These stars were usually discarded in previous similar studies.A scrutiny of our final results sheds light on selection effects present in our studies,which we propose to be the focus of future studies.In total,we find three late-type(2 G-type and 1 K-type)HVS and 21 high velocity star candidates,3 and 11 of which are new,respectively.Judging by their historical trajectories,which we calculate,all three HVS candidates could not have had Galactic center origins.Further monitoring is required to confirm their status.Several dozen hypervelocity star(HVS) candidates have been reported based on the second data release of Gaia(Gaia DR2). However, it has been proven that the radial velocities of some Gaia HVS candidates are not reliable. In this paper, we employ refined astrometric criteria to re-examine Gaia DR2,arriving at a more reliable sample of HVS and high velocity star candidates than those found by previous authors. We develop a method called Binary Escape Probability Analysis to identify some HVS candidates.This method allows us to work with stars having only two epochs of measured radial velocity. These stars were usually discarded in previous similar studies. A scrutiny of our final results sheds light on selection effects present in our studies, which we propose to be the focus of future studies. In total, we find three late-type(2 G-type and 1 K-type) HVS and 21 high velocity star candidates, 3 and 11 of which are new,respectively. Judging by their historical trajectories, which we calculate, all three HVS candidates could not have had Galactic center origins. Further monitoring is required to confirm their status.

关 键 词：STARS KINEMATICS and dynamics-evolution-statistics 

分 类 号：P152[天文地球—天文学]