A high-velocity star recently ejected by an intermediate-mass black hole in M15  

作　　者：Yang Huang Qingzheng Li Jifeng Liu Xiaobo Dong Huawei Zhang Youjun Lu Cuihua Du 

机构地区：[1]School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 100049,China [2]National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012,China [3]Yunnan Observatories,Chinese Academy of Sciences,Kunming 650011,China [4]New Cornerstone Science Laboratory,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012,China [5]Institute for Frontiers in Astronomy and Astrophysics,Beijing Normal University,Beijing 102206,China [6]Department of Astronomy,School of Physics,Peking University,Beijing 100871,China [7]Kavli Institute for Astronomy and Astrophysics,Peking University,Beijing 100871,China

出　　处：《National Science Review》2025年第2期23-28,共6页国家科学评论(英文版)

基　　金：supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0550103);the National Natural Science Foundation of China(12422303,11903027 and 11833006);the National Key R&D Program of China(2023YFA1608303 and 2019YFA0405503);support from the National Natural Science Foundation of China(11988101 and 11933004);the New Cornerstone Science Foundation through the New Cornerstone Investigator Program and the XPLORER PRIZE.;support from the National Natural Science Foundation of China(12373013);the National Natu-ral Science Foundation of China(11973001,12090040 and 12090044);the National Key R&D Program of China(2019YFA0405504).

摘　　要：The existence of intermediate-mass black holes(IMBHs)is crucial for understanding various astrophysical phenomena,yet their existence remains elusive,except for the LIGO-Virgo detection.We report the discovery of a high-velocity star J0731+3717,whose backward trajectory about 21 Myr ago intersected that of globular cluster M15 within the cluster tidal radius.Both its metallicity[Fe/H]and alpha-to-iron abundance ratio[α/Fe]are consistent with those of M15.Furthermore,its location falls right on the fiducial sequence of cluster M15 on the color-absolute magnitude diagram,suggesting similar ages.These findings support the notion that J0731+3717 was originally associated with M15 at a confidence level of‘seven nines’.We find that such a high-velocity star(V_(ej)=548_(−5)^(+6) km s^(−1))was most likely tidally ejected from as close as one astronomical unit to the center of M15,confirming an IMBH(≥100 Mwith a credibility of 98%)as the exclusive nature of the central unseen mass proposed previously.

关 键 词：intermediate-mass black hole Hills mechanism hypervelocity star globular cluster large-scale survey 

分 类 号：O17[理学—数学]