LMC origin of the hyper-velocity star HE 0437-5439
نویسندگان
چکیده
منابع مشابه
He 0437−5439 – an Unbound Hyper-velocity Main-sequence B-type Star *
We report the discovery of a 16 th magnitude star, HE 0437−5439, with a heliocentric radial velocity of +723 ± 3 km s −1. A quantitative spectral analysis of high-resolution optical spectra obtained with the VLT and the UVES – 2 – spectrograph shows that HE 0437−5439 is a main sequence B-type star with T eff =20 350 K, log(g) = 3.77, solar within a factor of a few helium abundance and metal con...
متن کاملLow Metallicity Indicates that the Hypervelocity Star HE 0437–5439 was Ejected from the LMC
We measure the metallicity of the unusual hypervelocity star HE 0437–5439 from high resolution spectroscopy to be half-solar. We determine a spectral type of B2 IV-III for the star and derive an effective temperature Teff = 21,500 ± 1,000 K and a surface gravity log(g) = 3.7 ± 0.2 (cgs). We also present BV time series photometry and find the star to be non-variable at the 0.02 mag level. We ref...
متن کاملA hypervelocity star from the Large Magellanic Cloud
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 and is located at a distance of 61 kpc from the Sun. With a mass of about 8M⊙, the travel time from the Galactic centre is of about 100Myr, much longer than its main sequence lifetime. Given the relatively small dista...
متن کاملHigh Velocity Star Formation in the Lmc
Light-echo measurements show that SN1987A is 425 pc behind the LMC disk. It is continuing to move away from the disk at 18 kms. Thus, it has been suggested that SN1987A was ejected from the LMC disk. However, SN1987A is a member of a star cluster, so this entire cluster would have to have been ejected from the disk. We show that the cluster was formed in the LMC disk, with a velocity perpendicu...
متن کاملAn unbound hyper - velocity subluminous O star
We report the discovery of an unbound hyper-velocity star, US 708, in the Milky Way halo, with a heliocentric radial velocity of +708±15 km s −1. A quantitative NLTE model atmosphere analysis of optical spectra obtained with LRIS at the Keck I telescope shows that US 708 is an extremely helium-rich (N He /N H =10) subluminous O type star with T eff = 44 500 K, log g = 5.23 at a distance of 19 k...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2008
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:200809391