1RXS J160929.1-210524

Starbox begin
name = 1RXS J160929.1-210524Starbox image


caption = The star and its ~8 x Jupiter mass planetary companion
credit = Gemini Observatory Starbox observe
epoch = J2000.0
equinox = J2000.0
constell = Scorpius
ra = RA|16|09|30.3SIMBAD link|GSC+06213-01358|GSC 06213-01358 -- Pre-main sequence Star (optically detected), database entry, SIMBAD. Accessed on line September 17, 2008.]
dec = DEC|−21|04|58Starbox character
class = K7VTable 1, Direct Imaging and Spectroscopy of a Planetary Mass Candidate Companion to a Young Solar Analog, David Lafrenière, Ray Jayawardhana, and Marten H. van Kerkwijk, submitted to "Astrophysical Journal Letters", arXiv|0809.1424, bibcode|2008arXiv0809.1424L.]
r-i =
v-r =
b-v =
u-b =
variable = T Tauri starStarbox astrometry
radial_v =
prop_mo_ra =
prop_mo_dec =
parallax =
p_error =
parallax_footnote =
dist_ly = 470 ± 70
dist_pc = 145 ± 20p. 1, Lafrenière et al. 2008.]
space_v_u =
space_v_v =
space_v_w = Starbox detail
source =
mass = 0.85±|0.20|0.10
radius = 1.35
gravity =
luminosity =
luminosity_bolometric =
luminosity_visual =
temperature = 4060±|300|200
metal =
rotation =
age = 5 millionStarbox catalog
names = 2MASS J16093030-2104589, GSC 06213-01358, PZ99 J160930.3-210459Starbox reference
Simbad = GSC+06213-01358
ARICNS =

1RXS J160929.1-210524 is a pre-main sequence star approximately 470 light-years away in the constellation of Scorpius. The star was identified as a 5 million year-old member of the Upper Scorpius subgroup of the Scorpius-Centaurus Association by Thomas Preibisch and coauthors in 1998.

Planetary system

In 2008, it was announced that astronomer David Lafreniere and collaborators used the Gemini Observatory to take pictures of the star which appeared to show a planet (designated "1RXS J160929.1-210524 b") orbiting the star at a great distance, some 330 times the distance that the Earth orbits the Sun. [ [http://news.bbc.co.uk/1/hi/sci/tech/7617031.stm Exoplanet 'circles normal star'] , "BBC News", September 15, 2008. Accessed on line September 17, 2008.] The object was labelled a planet by the discoverers as its inferred mass is comfortably below the limit above which an object can sustain deuterium fusion in its core (this limit corresponds to roughly 13 Jupiter masses), which is taken by the IAU's Working Group on Extrasolar Planets to be the dividing line between brown dwarfs and planets [cite web|url=http://www.dtm.ciw.edu/boss/definition.html|title=Definition of a "Planet"|publisher=Working Group on Extrasolar Planets (WGESP) of the International Astronomical Union|accessdate=2008-10-01] (note however that this criterion is not universally accepted: an alternative proposal is to regard a "planet" as an object that has formed by core accretion, regardless of whether or not deuterium fusion takes place in its interior [cite journal|url=http://adsabs.harvard.edu/abs/2008A&A...482..315B|title=Structure and evolution of super-Earth to super-Jupiter exoplanets. I. Heavy element enrichment in the interior|author=Baraffe, I.; Chabrier, G. and Barman, T.|year=2008|journal=Astronomy and Astrophysics|volume=482|issue=1|pages=315–332|doi=10.1051/0004-6361:20079321] ). The discoverers note that the object's location far from its star presents serious challenges to current models of planetary formation: the timescale to form a planet by core accretion at this distance from the star would be longer than the age of the system itself. One possibility is that the planet may have formed closer to the star and migrated outwards as a result of interactions with the disk or with other planets in the system. An alternative is that the planet formed "in situ" via the disk instability mechanism, where the disk fragments due to gravitational instability, though this would require an unusually massive protoplanetary disk.

OrbitboxOnePlanet
exoplanet = b (unconfirmed)
mass = 8±|4|1
separation = ~330

References

External links

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