SIMBAD references

2009A&A...507L..37T - Astronomy and Astrophysics, volume 507, L37-40 (2009/11-4)

SDSS J013655.91+242546.0 - an A-type hyper-velocity star from the outskirts of the Galaxy.


Abstract (from CDS):

Hyper-velocity stars (HVS) are moving so fast that they are unbound to the Galaxy. Dynamical ejection by a supermassive black hole is favoured to explain their origin. Locating the place of birth of an individual HVS is of utmost importance to understanding the ejection mechanism. SDSS J013655.91+242546.0 (J0136+2425 for short) was found amongst three high-velocity stars (drawn from a sample of more than 10000 blue stars), for which proper motions were measured. A kinematical as well as a quantitative NLTE spectral analysis was performed. When combined with the radial velocity (RV) and the spectroscopic distance, the trajectory of the star in the Galactic potential was reconstructed. J0136+2425 is found to be an A-type main-sequence star travelling at ≃590km/s, possibly unbound to the Galaxy and originating in the outer Galactic rim nowhere near the Galactic centre. J0136+2425 is the second HVS candidate with measured proper motion, besides the massive B star HD 271791, and also the second for which its proper motion excludes a Galactic centre origin and, hence, the SMBH slingshot mechanism. Most known HVS are late B-type stars of about 3M. With a mass of 2.45M, J0136+2425 resembles a typical HVS far more than HD 271791 does. Hence, this is the first time that a typical HVS is found not to originate in the Galactic centre. Its ejection velocity from the disk is so high (550km/s) that the extreme supernova binary scenario proposed for HD 271791 is very unlikely.

Abstract Copyright:

Journal keyword(s): stars: kinematics - stars: individual: SDSS J013655.91+242546.0 - stars: atmospheres - line profiles

Simbad objects: 5

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