View Laura K. Kinoshita's profileAstronomers using the Gemini North telescope announced this week they may have taken a direct image of a large, young planet orbiting very far away from a star in the Scorpio constellation.
While more than 300 planets have been discovered orbiting stars other than our Sun, few resemble orbits of the large planets in our own solar system. So researchers have been looking for ways to find planets that orbit stars at much greater distances than what other planet-finding techniques turn up.
As a result, Dr. David Lafreniere and Dr. Ray Jayawardhana at the University of Toronto announced the discovery of a planet that may be orbiting a star at 10 times the Pluto-Sun distance. The planet, about eight times the size of Jupiter, orbits 330 AU from a solar-mass star. For comparison, the average distance between Pluto and the Sun is 39 AU.
If this new planet is gravitationally bound to the host star -- and that's a BIG if -- it would be the smallest planet ever imaged around a normal star, and its existence at such a large separation would pose a serious challenge to theories of star and planet formation.
So far there's no evidence. But, the Toronto researchers say, it's highly unlikely to be a free-floating planet. It could be a planet on a highly eccentric orbit, or a planet that suffered a major gravitational disturbance. Regardless, the very existence of the system challenges theories of planet and star formation.
To learn more, researcher will need to find out more about the planet's orbit. They will also be looking for closer-in planets and evidence of a large debris disk.
The discovery of a possible low-mass planetary companion to the star 1RXS J160929.1-210524 is described in the Sept. 8th preprint of the Astrophysical Journal. (http://arxiv.org/PS_cache/arxiv/pdf/0809/0809.1424v1.pdf
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