SDSS J013655.91+242546.0-an A-type hyper-velocity star from the outskirts of the Galaxy
Tillich A, Przybilla N, Scholz RD, Heber U, Heber U (2009)
Publication Status: Published
Publication Type: Journal article
Publication year: 2009
Journal
Publisher: EDP SCIENCES S A
Book Volume: 507
Pages Range: L37-L40
Journal Issue: 2
DOI: 10.1051/0004-6361/200913173
Abstract
Context. 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.Aims. Locating the place of birth of an individual HVS is of utmost importance to understanding the ejection mechanism.Methods. SDSS J013655.91+242546.0 (J0136+2425 for short) was found amongst three high-velocity stars (drawn from a sample of more than 10 000 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.Results. J0136+2425 is found to be an A-type main-sequence star travelling at approximate to 590 km s(-1), possibly unbound to the Galaxy and originating in the outer Galactic rim nowhere near the Galactic centre.Conclusions. 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 3 M(circle dot). With a mass of 2.45 M(circle dot), 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 (550 km s(-1)) that the extreme supernova binary scenario proposed for HD 271791 is very unlikely.
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APA:
Tillich, A., Przybilla, N., Scholz, R.-D., Heber, U., & Heber, U. (2009). SDSS J013655.91+242546.0-an A-type hyper-velocity star from the outskirts of the Galaxy. Astronomy & Astrophysics, 507(2), L37-L40. https://doi.org/10.1051/0004-6361/200913173
MLA:
Tillich, A., et al. "SDSS J013655.91+242546.0-an A-type hyper-velocity star from the outskirts of the Galaxy." Astronomy & Astrophysics 507.2 (2009): L37-L40.
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