HVS 7 --
hyper-velocity star 7, otherwise known as SDSS J113312.12+010824.9 is a rare star that has been accelerated to faster than our
Milky Way Galaxy's
escape velocity.[7][8] In 2013 a team under N. Przybilla wrote that the star had a chemically peculiar
photosphere, which masked its origins.[7] The star was first cataloged during the
Sloan Digital Sky Survey. It was identified as a hyper-velocity star in 2006.[8]
The star has a
chemically peculiar spectrum, roughly matching a B-type
subdwarf. Stars in this region of the
Hertzsprung–Russell diagram are expected to either be hot
horizontal branch stars, low-mass helium-burning objects, or moderate mass hydrogen-burning stars slightly below the
main sequence. The high rotational velocity of HVS 7 means it is likely to be a young star near the main sequence, around 150 million years old and 3.7 times the mass of the sun.[7]
^Brown, Warren R.; Geller, Margaret J.; Kenyon, Scott J.; Kurtz, Michael J.; Bromley, Benjamin C. (2007). "Hypervelocity Stars. III. The Space Density and Ejection History of Main-Sequence Stars from the Galactic Center". The Astrophysical Journal. 671 (2): 1708.
arXiv:0709.1471.
Bibcode:
2007ApJ...671.1708B.
doi:
10.1086/523642.
S2CID15074398.
^Harris, Hugh C.; Liebert, James; Kleinman, S. J.; Nitta, Atsuko; Anderson, Scott F.; Knapp, Gillian R.; Krzesiński, Jurek; Schmidt, Gary; Strauss, Michael A.; Vanden Berk, Dan; Eisenstein, Daniel; Hawley, Suzanne; Margon, Bruce; Munn, Jeffrey A.; Silvestri, Nicole M.; Smith, J. Allyn; Szkody, Paula; Collinge, Matthew J.; Dahn, Conard C.; Fan, Xiaohui; Hall, Patrick B.; Schneider, Donald P.; Brinkmann, J.; Burles, Scott; Gunn, James E.; Hennessy, Gregory S.; Hindsley, Robert; Ivezić, Zeljko; Kent, Stephen; et al. (2003). "An Initial Survey of White Dwarfs in the Sloan Digital Sky Survey". The Astronomical Journal. 126 (2): 1023.
arXiv:astro-ph/0305347.
Bibcode:
2003AJ....126.1023H.
doi:
10.1086/376842.
S2CID118927660.
^Adelman-Mccarthy, J. K.; et al. (2011). "VizieR Online Data Catalog: The SDSS Photometric Catalog, Release 8 (Adelman-McCarthy+, 2011)". VizieR On-line Data Catalog.
Bibcode:
2011yCat.2306....0A.
^
abcd
Przybilla, N.; Nieva, M. F.; Tillich, A.; Heber, U.; Butler, K.; Brown, W. R. (2008). "HVS 7: A chemically peculiar hyper-velocity star". Astronomy & Astrophysics. 488 (2): L51–L54.
arXiv:0810.0864.
Bibcode:
2008A&A...488L..51P.
doi:
10.1051/0004-6361:200810455.
S2CID56111543. Such a surface abundance pattern is caused by atomic diffusion in a possibly magnetically stabilised, non-convective atmosphere. Hence all chemical information on the star's place of birth and its evolution has been washed out. High precision astrometry is the only means to validate a GC origin for HVS 7.
^
ab
Brown, Warren R.; Geller, Margaret J.; Kenyon, Scott J.; Kurtz, Michael J. (2006). "Hypervelocity Stars. I. The Spectroscopic Survey". The Astrophysical Journal. 647 (1): 303–311.
arXiv:astro-ph/0604111.
Bibcode:
2006ApJ...647..303B.
doi:
10.1086/505165.
S2CID15561164. Here we report the two most recently discovered HVSs: SDSS J110557.45+093439.5 and possibly SDSS J113312.12+010824, traveling with Galactic rest-frame velocities at least +508+/-12 and +418+/-10 km s-1, respectively.