A giant exoplanet (planet outside of our own solar system), that is in the most distant orbit ever seen around its host star, has been recently discovered. Dubbed HD 106906 b, the newly discovered planet is relatively young (13 million years old, compare this to our 4.5 billion years old Earth) and bigger than any other planet discovered till date. It is 11 times the size of Jupiter, and that’s what makes it a most singular discovery.
According to established planet formation theories, planets form around their stars beginning as asteroid-like bodies, slowly gathering mass through material present in the residual gas and dust of the host stars. For all this to happen, a planet has to be close to its star. HD 106906 b is 650 astronomical units (AU) away from its star, where 1 AU is the average distance between the Earth and the Sun. The newfound exoplanet is not only too far away to be formed according to existing planet formation theories, it’s also too heavy to be formed in such a manner.
“This system is especially fascinating because no model of either planet or star formation fully explains what we see,” says lead researcher Vanessa Bailey.
An alternative hypothesis similar to the formation of binary star systems has been suggested to help explain the case of HD 106906 b. ”A binary star system can be formed when two adjacent clumps of gas collapse more or less independently to form stars, and these stars are close enough to each other to exert a mutual gravitation attraction and bind them together in an orbit,” Bailey explained. In this case too, the star and the planet may have formed independently, but the planet couldn’t accumulate enough material to help it grow into a star.
One problem with the applicability of binary star hypothesis is that usually the mass ratio of the two stars in a binary star system is not more than 1 is to 10. HD 106906 b’s star is 100 times heavier than the planet.
The discovery of HD 106906 b raises new questions and challenges our accepted knowledge of the universe. This enormous planet may be the key to understanding the various mysteries of the big, wild universe we inhabit. With detectable leftover material still present from the time of formation of the system, scientists are hopeful of using it to getting answers to questions that this newfound planet raises.