A Galactic origin for HE 0437-5439, the hypervelocity star near the Large Magellanic Cloud

Warren R. Brown, Jay Anderson, Oleg Y. Gnedin, Howard E. Bond, Margaret J. Geller, Scott J. Kenyon, Mario Livio

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

We use Hubble Space Telescope imaging to measure the absolute proper motion of the hypervelocity star (HVS) HE 0437-5439, a short-lived B star located in the direction of the Large Magellanic Cloud (LMC). We observe (μα,μδ) = (+0.53 ± 0.25(stat) ± 0.33(sys), +0.09 ± 0.21(stat) ± 0.48(sys)) mas yr-1. The velocity vector points directly away from the center of the Milky Way; an origin from the center of the LMC is ruled out at the 3σ level. The flight time of the HVS from the Milky Way exceeds its main-sequence lifetime, thus its stellar nature requires it to be a blue straggler. The large space velocity rules out a Galactic-disk ejection. Combining the HVS's observed trajectory, stellar nature, and required initial velocity, we conclude that HE 0437-5439 was most likely a compact binary ejected by the Milky Way's central black hole.

Original languageEnglish (US)
Pages (from-to)L23-L27
JournalAstrophysical Journal Letters
Volume719
Issue number1 PART 2
DOIs
StatePublished - Aug 10 2010

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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