Washington, Dec 8 (): Astronomers have discovered a planet 11 times the size of Jupiter revolving around its host star in the farthest-ever orbit observed so far among all the planetary systems known.
An international team of astronomers, headed by a University of Arizona graduate student, discovered the planet HD 106906 b around a Sun-like star. The team has revealed the most distantly orbiting planet found to date around a single, sun-like star. It is the first exoplanet – a planet outside of our solar system discovered at the UA. It revolves its host star at 650 times the average Earth-Sun distance.
Vanessa Bailey, who led the research said that this system is especially interesting because no model of either planet or star formation fully explains what we see.
It is thought that planets close to their stars, like Earth, merge from small asteroid-like bodies born in the primordial disk of dust and gas that surrounds a forming star. However, this process acts too slowly to grow giant planets far from their star.
Another proposed mechanism is that giant planets can form from a fast, direct collapse of disk material. However, primordial disks hardly contain enough mass in their outer reaches to allow a planet like HD 106906 b to form. Some other theories have also been put forward, including formation like a mini binary star system.
In the HD 106906 system, the star and planet may have collapsed independently, but the materials that clumped together to form the planet were insufficient for it to grow large enough to ignite into a new star, Bailey said.
There are still problems with this set-up. For one, difference between the masses of two stars in a binary system is typically no more than a ratio of 10 to 1. Researchers are also interested to study the new planet, because leftover material from when the planet and star formed can still be detected.