SDSS J090745.0+024507

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SDSS J090745.0+024507
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Hydra
Right ascension  09h 07m 44.99 s
Declination +02° 45′ 06.9″
Spectral typeB9
Other designations
SDSS J090744.99+024506.8
Database references

SDSS J090744.99+024506.8 (SDSS 090745.0+024507), is a short period variable star which has a Galactic rest-frame radial velocity of 709 km/s. It is possible that it was originally part of a binary system that was tidally disrupted by the supermassive black hole at the centre of the Milky Way, causing it to be ejected at high velocity. Its effective temperature is 10,500 k (spectral type B9) and its age is estimated at 350 million years. It has a heliocentric distance of 71 kpc. It was ejected from the centre of the galaxy less than 100 million years ago, which implies the existence of a population of young stars at the galactic centre less than 100 million years ago.[1]

Christened by the astronomer Warren Brown as the Outcast Star, it is the first discovered member of a class of objects named hypervelocity stars.[2] It was discovered in 2005 at the MMT Observatory of the Harvard-Smithsonian Center for Astrophysics (CfA), by astronomers Warren Brown, Margaret J. Geller, Scott J. Kenyon and Michael J. Kurtz.[3]


  1. ^ Cesar I. Fuentes; K. Z. Stanek; B. Scott Gaudi; Brian A. McLeod; Slavko B. Bogdanov; Joel D. Hartman; Ryan C. Hickox; Matthew J. Holman (21 July 2005). The Hypervelocity Star SDSS J090745.0+024507 is a Short-Period Variable. Cornell University Library (Report). arXiv:astro-ph/0507520. Bibcode:2006ApJ...636L..37F. doi:10.1086/499233. Accessed 18 January 2016.
  2. ^ Berardelli, Phil (February 10, 2005), "In The Stars: Odd Stars, Odder Planets", Space Daily
  3. ^ Brown, Warren R.; Geller, Margaret J.; Kenyon, Scott J. & Kurtz, Michael J. (2005), "Discovery of an Unbound Hypervelocity Star in the Milky Way Halo", Astrophysical Journal, 622 (1): L33–L36, arXiv:astro-ph/0501177, Bibcode:2005ApJ...622L..33B, doi:10.1086/429378

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