US 708 – an unbound hyper-velocity subluminous O star
نویسندگان
چکیده
منابع مشابه
An 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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We have discovered a star, SDSS J090745.0+024507, leaving the Galaxy with a heliocentric radial velocity of +853± 12 km s, the largest velocity ever observed in the Milky Way halo. The star is either a hot blue horizontal branch star or a B9 main sequence star with a heliocentric distance ∼55 kpc. Corrected for the solar reflex motion and to the local standard of rest, the Galactic rest-frame v...
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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 کاملHVS 7 : a chemically peculiar hyper - velocity star ⋆
Context. Hyper-velocity stars are suggested to originate from the dynamical interaction of binary stars with the supermassive black hole in the Galactic centre (GC), which accelerates one component of the binary to beyond the Galactic escape velocity. Aims. The evolutionary status and GC origin of the hyper-velocity star SDSS J113312.12+010824.9 (aka HVS 7) is constrained from a detailed study ...
متن کاملStellar dynamics. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova.
Hypervelocity stars (HVSs) travel with velocities so high that they exceed the escape velocity of the Galaxy. Several acceleration mechanisms have been discussed. Only one HVS (US 708, HVS 2) is a compact helium star. Here we present a spectroscopic and kinematic analysis of US 708. Traveling with a velocity of ~1200 kilometers per second, it is the fastest unbound star in our Galaxy. In recons...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2005
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:200500212