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Hypervelocity stars (HVSs) are stars ejected from the Galactic Centre (GC) through tidal interactions with the central supermassive black hole. Formed in the immediate vicinity of Sgr~A$^\ast$, these stars are accelerated to velocities high…

Astrophysics of Galaxies · Physics 2026-05-13 Manuel Cavieres , Sergey E. Koposov , Elena Maria Rossi , Zephyr Penoyre , Sill Verberne

Hypervelocity stars are believed to be ejected out from the Galactic center through dynamical interactions of (binary) stars with the central massive black hole(s). In this letter, we report 13 metal-poor F-type hypervelocity star…

Solar and Stellar Astrophysics · Physics 2015-06-03 Yinbi Li , Ali Luo , Gang Zhao , Youjun Lu , Juanjuan Ren , Fang Zuo

We report the discovery of DESI-HVS1, a hypervelocity star (HVS) candidate identified from DESI DR1 spectroscopy and Gaia DR3 astrometry. DESI-HVS1 is an old, low-mass, metal-poor F-type star with a mass of $0.8\,M_\odot$, an age of…

Astrophysics of Galaxies · Physics 2026-05-14 Shunhong Deng , Yang Huang , Haozhu Fu , Yongkang Sun , Qikang Feng , Guoyang Chen , Huawei Zhang

The dense cores of Milky Way globular clusters (GCs) play host to a variety of dynamical encounters between stellar objects, which can accelerate stars to velocities high enough to escape the GC. The most extreme examples of these…

Astrophysics of Galaxies · Physics 2025-06-23 Fraser A. Evans , Steffani M. Grondin , Claire S. Ye , Jeremy Webb , Alexander Laroche , Jo Bovy

We study three processes that eject hypervelocity (>10^3 km/s) stars from the Galactic center: (i) close encounters of two single stars; (ii) tidal breakup of binary stars by the central black hole, as originally proposed by Hills; and…

Astrophysics · Physics 2008-11-26 Qingjuan Yu , Scott Tremaine

Hypervelocity stars (HVS) are a class of stars moving at high enough velocities to be gravitationally unbound from the Galaxy. Ejection from a close binary system in which one of the components undergoes a thermonuclear supernova (SN) has…

Solar and Stellar Astrophysics · Physics 2020-09-09 Patrick Neunteufel

The mass assembly history of the Milky Way can inform both theory of galaxy formation and the underlying cosmological model. Thus, observational constraints on the properties of both its baryonic and dark matter contents are sought. Here we…

Astrophysics of Galaxies · Physics 2017-01-24 Elena M. Rossi , T. Marchetti , M. Cacciato , M. Kuiack , R. Sari

The disruption of binary stars by the tidal field of the black hole in the Galactic Center can produce the hypervelocity stars observed in the halo. We use numerical models to simulate the full spectrum of observable velocities of stars…

Hypervelocity stars (HVS) traverse the Galaxy from the central black hole to the outer halo. We show that the Galactic potential within 200 pc acts as a high pass filter preventing low velocity HVS from reaching the halo. To trace the…

Astrophysics · Physics 2009-11-13 S. J. Kenyon , B. C. Bromley , M. J. Geller , W. R. Brown

Stars ejected from the Galactic centre can be used to place important constraints on the Milky Way potential. Since existing hypervelocity stars are too distant to accurately determine orbits, we have conducted a search for nearby…

Astrophysics of Galaxies · Physics 2016-12-06 Yanqiong Zhang , Martin C. Smith , Jeffrey L. Carlin

The discovery of hypervelocity stars (HVS) leaving our galaxy with speeds of nearly $10^{3}$ km s$^{-1}$ has provided strong evidence towards the existence of a massive compact object at the galaxy's center. HVS ejected via the disruption…

Astrophysics of Galaxies · Physics 2015-06-18 James Guillochon , Abraham Loeb

Hypervelocity stars (HVSs) travel so fast that they may leave the Galaxy. The tidal disruption of a binary system by the supermassive black hole in the Galactic center is widely assumed to be their ejection mechanism. To test the hypothesis…

Solar and Stellar Astrophysics · Physics 2018-07-18 Andreas Irrgang , Simon Kreuzer , Ulrich Heber , Warren Brown

In recent years several hypervelocity stars (HVSs) have been observed in the halo of our Galaxy. Such stars are thought to be ejected through dynamical interactions near the massive black hole (MBH) in the Galactic center. Three scenarios…

Astrophysics · Physics 2008-12-18 Hagai B. Perets

The hypervelocity star (HVS) survey conducted at the Multiple Mirror Telescope (MMT) identified 42 B-type stars in the Galactic halo whose radial velocity in the Galactic rest-frame exceeds $+275\,$km$\,$s${}^{-1}$. In order to unravel the…

Solar and Stellar Astrophysics · Physics 2020-05-13 S. Kreuzer , A. Irrgang , U. Heber

Hypervelocity stars (HVSs) are produced by the Hills mechanism when a stellar binary is disrupted by a supermassive black hole (SMBH). The HVS Survey detected 21 unbound B-type main-sequence stars in the Milky Way's outer halo that are…

Hypervelocity stars (HVSs) represent a unique class of objects capable of escaping the gravitational pull of the Milky Way due to extreme acceleration events, such as close encounters with the supermassive black hole at the Galactic center…

Astrophysics of Galaxies · Physics 2025-04-22 Yongkang Sun , Yang Huang , Jifeng Liu , Haozhu Fu , Huawei Zhang , Yinbi Li , Cuihua Du , Jianrong Shi , Xiao Kong

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…

Solar and Stellar Astrophysics · Physics 2020-05-13 Jiao Li , Shi Jia , Yan Gao , Deng-Kai Jiang , Thomas Kupfer , Ulrich Heber , Chao Liu , Xue-Fei Chen , Zhan-Wen Han

We present the serendipitous discovery of the fastest Main Sequence hyper-velocity star (HVS) by the Southern Stellar Stream Spectroscopic Survey (S5). The star S5-HVS1 is a $\sim 2.35$ M$_\odot$ A-type star located at a distance of $\sim…

The paucity of hypervelocity stars (HVSs) known to date has severely hampered their potential to investigate the stellar population of the Galactic Centre and the Galactic Potential. The first Gaia data release gives an opportunity to…

Astrophysics of Galaxies · Physics 2017-05-30 T. Marchetti , E. M. Rossi , G. Kordopatis , A. G. A. Brown , A. Rimoldi , E. Starkenburg , K. Youakim , R. Ashley

We present high-precision photometry of the hypervelocity star SDSS J090745.0+024507 (HVS), which has a Galactic rest-frame radial velocity of v=709 km/s, and so has likely been ejected from the supermassive black hole in the Galactic…