HE 0437-5439

HE 0437-5439

Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Dorado
Right ascension 04h 38m 12.772s[1]
Declination −54° 33′ 11.86″
Apparent magnitude (V) 16.42
Characteristics
Spectral type BV or sdB+F
Astrometry
Distance200,000 ly
Details
Mass8 M☉
Age25 Myr
Other designations
GSC2 S01132011256, HE 0437-5439, [BGK2006] HV 3, HVS3.
Database references
SIMBADdata

HE 0437-5439 is a massive, unbound hypervelocity star (HVS), also called HVS3.[2] It is a main sequence B-type star located in the Dorado constellation. It was discovered in 2005 with the Kueyen 8.2-metre (320 in) telescope, which is part of the European Southern Observatory's Very Large Telescope array. HE 0437-5439 is a young star, with an age of around 30 million years.[3] The mass of the star is almost nine times greater than the mass of the Sun[4] and the star is located 200,000 light years away in the direction of the Dorado constellation, 16 degrees northwest of the Large Magellanic Cloud (LMC) and farther away than the LMC.[3] The star appears to be receding at an extremely high velocity of 723 kilometres per second (449 mi/s), or 2,600,000 kilometres per hour (1,600,000 mph). At this speed, the star is no longer gravitationally bound and will leave the Milky Way galaxy system and escape into intergalactic space. It was thought to have originated in the LMC and been ejected from it soon after birth. This could happen if it originally was one of a pair of stars and if there is a supermassive black hole in the LMC.[4]

In 2010 a study was published in which its proper motion was estimated using images from the Hubble Space Telescope from 2006 and 2009. This ruled out the possibility that the star came from the Large Magellanic Cloud, but was consistent with the hypothesis that it was ejected from the center of the Milky Way. Given its velocity, this would have occurred 100 million years ago. However, the star seems to be at most 20 million years old, which implies that it is a blue straggler, a star born from the merger of a binary star system, which was earlier ejected from the center of the Milky Way. In order for this to happen, there must have originally been a three-star system, or else there were two black holes and just the two stars.[2]

  1. ^ Cite error: The named reference aa was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Brown was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference ESO051109 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Sciencedaily was invoked but never defined (see the help page).