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arXiv 2602.02666astro-ph.GA
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IRS 9: 银河系中心动态弹射恒星的案例

IRS 9: The Case for a Dynamically-Ejected Star from the Galactic Center

UCLA Department of Physics and Astronomy(加州大学洛杉矶分校物理与天文学系);Mani L. Bhaumik Institute for Theoretical Physics, Department of Physics and Astronomy, UCLA(加州大学洛杉矶分校曼尼·L·巴乌米克理论物理研究所物理与天文学系);Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University(西北大学天体物理学跨学科探索与研究中心);Space Telescope Science Institute(太空望远镜科学研究所)

Matthew Hosek, Tuan Do, Smadar Naoz, Sanaea C. Rose, Gregory D. Martinez, Andrea M. Ghez, Rebecca Lewis-Merrill, Jessica R. Lu, Shoko Sakai, Jay Anderson

AI总结:

研究IRS 9在银河系中心的高速运动,探讨其可能经历的动态弹射机制及对核区动态过程的理解

摘要:

测量银河系中心(GC)的恒星运动为了解银河核区的动态过程提供了独特见解。我们对23个位于SgrA* 45

英文摘要:

Measuring stellar motions at the Milky Way's Galactic center (GC) provides unique insight into the dynamical processes within galactic nuclei. We present proper motion measurements for 23 SiO-maser emitting stars within 45'' of SgrA*, including four previously reported to have velocities exceeding their local escape velocities (i.e., they are "locally unbound" from the GC). Derived from 14 epochs of HST WFC3-IR observations (2010 - 2023), our measurements have a median precision of 0.038 mas/yr - up to ~100x more precise then previous constraints for some sources. By combining these proper motions with published radial velocities, we derive updated 3D velocities for the masers and find that only one is locally unbound (IRS 9; v3d = 370 +/- 1.2 km/s). Orbit integrations place the first constraints on the orbit of IRS 9, which is bound to the GC at larger radii with r_peri >= 0.100 +/- 0.005 pc and r_apo >= 5.25 +/- 0.18 pc. IRS 9's high velocity relative to stars at similar radii in the Nuclear Star Cluster makes it a candidate to have experienced a strong dynamical interaction in order to place it on its orbit. We explore the Hills mechanism as a possible origin, but binary evaporation and ejection velocity limits indicate that IRS 9 is unlikely to have experienced such an event in the past 0.4 Myr (the timescale constrained by the orbit integrations). Alternative mechanisms that could produce IRS 9 include binary supernova disruption, two-body interactions, and stellar collisions. Identifying additional stars like IRS 9 will be essential for understanding these various dynamical processes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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