S5-HVS1 is an A-type main-sequence star notable as the fastest one detected as of November 2019, and has been determined to be traveling at 1,755 km/s (3,930,000 mph). The star is in the Grus (or Crane) constellation in the southern sky, and about 29,000 light-years from Earth. According to astronomers, S5-HVS1 was ejected from the Milky Waygalaxy after interacting with Sagittarius A*, the supermassive black hole at the center of the galaxy. It is possible that it was originally part of a binary system that was tidally disrupted by the supermassive black hole, causing it to be ejected. If this is the case, that it was flung out of the galaxy by the central black hole, it is then the first example of a star that has undergone the Hills mechanism.
The star's discovery has been credited to Sergey Koposov, assistant professor of physics at Carnegie Mellon University, as part of the Southern Stellar Stream Spectroscopic Survey (S5). The designation HVS1 refers to hypervelocity stars (HVS).
^ abcOverbye, Dennis (14 November 2019). "A Black Hole Threw a Star Out of the Milky Way Galaxy - So long, S5-HVS1, we hardly knew you". The New York Times. Retrieved 18 November 2019.
^ abcdKoposov, Sergey E.; et al. (11 November 2019). "Discovery of a nearby 1700 km/s star ejected from the Milky Way by Sgr A*". Monthly Notices of the Royal Astronomical Society. arXiv:1907.11725. doi:10.1093/mnras/stz3081.
^Starr, Michelle (31 July 2019). "Bizarre Star Found Hurtling Out of Our Galaxy Centre Is Fastest of Its Kind Ever Seen". ScienceAlert.com. Retrieved 18 November 2019.
^Irving, Michael (13 November 2019). "Fastest star ever found is being flicked out of the Milky Way". NewAtlas.com. Retrieved 18 November 2019.
^Imster, Imster (18 November 2019). "Black hole hurls star out of Milky Way - Astronomers have spotted a star – S5-HVs1 – speeding out of the Milky Way at around 4 million miles (more than 6 million km) per hour. They believe it's being ejected from our galaxy after venturing too near the giant black hole at the Milky Way's heart about 5 million years ago". Earth & Sky. Retrieved 18 November 2019.
^Gohd, Chelsea (12 November 2019). "A Star Ejected from the Milky Way's 'Heart of Darkness' Has Reached a Mind-Blowing Speed - It is a visitor from a strange land". Space.com. Retrieved 18 November 2019.
^Staff (15 November 2019). "A Runaway Star Ejected from the Galactic Heart of Darkness". Carnegie-Mellon University. Retrieved 18 November 2019.
^Lincoln, Don (13 November 2019). "Supermassive Black Hole Ejects Star From Milky Way Galaxy". Forbes. Retrieved 18 November 2019.
^Plait, Phil (13 November 2019). "Our Local Supermassive Black Hole Shot A Star Right Out Of THe Galaxy". Bad Astronomy. Retrieved 19 November 2019.
^Carnegie Mellon University, , Science Daily, 12 November 2019
Video (animated; 0:22) – S5-HVS1 ejection from Milky Way on YouTube
Video (animated; 1:03) – S5-HVS1 ejection from Milky Way on YouTube