Open AccessA hypervelocity star from the Large Magellanic Cloud
Author(s) -
Gualandris Alessia,
Portegies Zwart Simon
Publication year - 2007
Publication title -
monthly notices of the royal astronomical society: letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.067
H-Index - 122
eISSN - 1745-3933
pISSN - 1745-3925
DOI - 10.1111/j.1745-3933.2007.00280.x
Subject(s) - physics , hypervelocity , astrophysics , large magellanic cloud , black hole (networking) , stars , astronomy , milky way , star (game theory) , computer network , routing protocol , routing (electronic design automation) , computer science , link state routing protocol
We study the acceleration of the star HE 0437−5439 to hypervelocity and discuss its possible origin in the Large Magellanic Cloud (LMC). The star has a radial velocity of 723 km s −1 and is located at a distance of 61 kpc from the Sun. With a mass of about 8 M ⊙ , the traveltime from the Galactic Centre is about 100 Myr, much longer than its main‐sequence lifetime. Given the relatively small distance to the LMC (18 kpc), we consider it likely that HE 0437−5439 originated in the Cloud rather than in the Galactic Centre like the other hypervelocity stars. The minimum ejection velocity required to travel from the LMC to its current location within its lifetime is about 500 km s −1 . Such a high velocity can only be obtained in a dynamical encounter with a massive black hole. We perform three‐body scattering simulations in which a stellar binary encounters a massive black hole, and find that a black hole more massive than 10 3 M ⊙ is necessary to explain the high velocity of HE 0437−5439. We look for possible parent clusters for HE 0437−5439, and find that NGC 2100 and 2004 are young enough to host stars coeval to HE 0437−5439 and dense enough to produce an intermediate‐mass black hole able to eject an 8‐M ⊙ star with hypervelocity.