2024/06/03 by Yang Huang, Qingzheng Li, Huang, Yang +11 · 3 citations
Engineering · Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Mechanics and Biomechanics Studies #Pulsars and Gravitational Waves Research #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.2406.00923
openalex publication_date 2024/06/03 · openalex created_date 2024/06/07 · openalex updated_date 2026/08/01
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 intersects that of globular cluster M15 within the cluster tidal radius. Both its metallicity [Fe/H] and its alpha-to-iron abundance ratio [α/Fe] are consistent with those of M15. Furthermore, its location falls right on the fiducial sequence of the cluster M15 on the color-absolute magnitude diagram, suggesting similar ages. These support that J0731+3717 is originally associated with M15 at a confidence level of "seven nines". We find that such a high-velocity star (V\rm ej = 548+6-5 km s-1) was most likely tidally ejected from as close as one astronomical unit to the center of M15, confirming an IMBH (≥ 100 M\odot with a credibility of 98%) as the exclusive nature of the central unseen mass proposed previously.