1RXS J160929.1−210524
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| Observation data Epoch J2000.0 Equinox J2000.0 |
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| Constellation | Scorpius |
| Right ascension | 16h 09m 30.3s[1] |
| Declination | −21° 04′ 58″[1] |
| Characteristics | |
| Spectral type | K7V[2] |
| Variable type | T Tauri star |
| Astrometry | |
| Distance | 470 ± 70 ly (145 ± 20[2] pc) |
| Details | |
| Mass | 0.85+0.20 −0.10[2] M☉ |
| Radius | 1.35[2] R☉ |
| Temperature | 4060+300 −200[2] K |
| Age | 5 million[2] years |
| Other designations | |
| Database references | |
| SIMBAD | data |
1RXS J160929.1-210524 is a pre–main sequence star nearly 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.
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[edit] Planetary system
On 8 September 2008, it was announced that astronomer David Lafrenière and collaborators used the Gemini Observatory to take pictures of the star which appeared to show a planet (designated 1RXS J160929.1-210524 b). The apparent planet is very large—about eight times the mass of Jupiter,[3] orbiting the star at a distance of 330 AU (roughly 50 billion kilometres or 31 billion miles).[4] The orbital status of the companion planet was confirmed in a paper submitted on 15 June 2010 to The Astrophysical Journal.[5][6] This makes it the smallest known exoplanet orbiting its host at such a distance. It is also the first announced directly imaged exoplanet orbiting a sun-like star, and the 2nd directly imaged exoplanet to have spectrum taken (after 2M1207b).[3]
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 because of gravitational instability, though this would require an unusually massive protoplanetary disk.[2]
| Companion | Mass | Observed separation (AU) |
| b | 8+4 −1[2] MJ |
~330[2] |
[edit] See also
[edit] References
- ^ a b GSC 06213-01358 – Pre-main-sequence Star (optically detected), database entry, SIMBAD. Accessed on line September 17, 2008.
- ^ a b c d e f g h i Lafrenière, David; Jayawardhana, Ray; Van Kerkwijk, Marten H. (2008). "Direct Imaging and Spectroscopy of a Planetary-Mass Candidate Companion to a Young Solar Analog". The Astrophysical Journal 689 (2): L153. Bibcode 2008ApJ...689L.153L. doi:10.1086/595870.
- ^ a b Fazekas, Andrew (June 30, 2010). ""First" Picture of Planet Orbiting Sunlike Star Confirmed". National Geographic. http://news.nationalgeographic.com/news/2010/06/100630-science-space-planets-first-picture-confirmed/. Retrieved July 1, 2010.
- ^ "Exoplanet 'circles normal star'". BBC News. September 15, 2008. http://news.bbc.co.uk/1/hi/sci/tech/7617031.stm. Retrieved September 17, 2008.
- ^ Lafrenière, David; Jayawardhana, Ray; van Kerkwijk, Marten H. (2010). "The Directly Imaged Planet around the Young Solar Analog 1RXS J160929.1-210524: Confirmation of Common Proper Motion, Temperature and Mass". The Astrophysical Journal 719 (1): 497. arXiv:1006.3070. Bibcode 2010ApJ...719..497L. doi:10.1088/0004-637X/719/1/497.
- ^ Kruesi, Liz (June 22, 2010). "Astronomers verify directly imaged planet". Astronomy Magazine. http://cs.astronomy.com/asycs/blogs/astronomy/2010/06/22/astronomers-verify-directly-imaged-planet.aspx. Retrieved July 1, 2010.[dead link]
[edit] External links
- "First Picture of Likely Planet around Sun-like Star". Gemini Observatory. 2008-09-15. http://www.gemini.edu/node/11126. Retrieved 2008-09-16.
- Jean Schneider (2011). "Notes for star 1RXS1609". Extrasolar Planets Encyclopaedia. http://exoplanet.eu/star.php?st=1RXS1609. Retrieved 30 September 2011.
- Astronomy Picture of the Day - Companion of a Young, Sun-like Star Confirmed - 2010 July 4
