1RXS J160929.1−210524

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, orbiting the star at a distance of 330 AU (roughly 50 billion kilometres or 31 billion miles). The orbital status of the companion planet was confirmed in a paper submitted on 15 June 2010 to The Astrophysical Journal. 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.

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.

^{Source: WIKIPEDIA}