This planet shouldn't exist

A giant planet has been found orbiting its star at more than 650 times the distance between the Earth and Sun, leaving astronomers puzzled.The planet, which bears the catchy name of HD 106906 b, is interesting as it doesn't match up with any of our theories of how planets form. Instead, it's thought it may be a tiny, failed star.


"This system is especially fascinating because no model of either planet or star formation fully explains what we see," said Vanessa Bailey form the University of Arizona, who led the research, published in Earth and Planetary Astrophysics.There are two main ways we think planets form. The first is that small asteroid-like bodies gradually grow larger from the disc of material that surrounds a forming star. That's how we think Earth formed.
The second is when giant planets, like Jupiter, form from the fast, direct collapse of disk material. The problem with this theory is that the outer disk doesn't normally contain enough material for a planet as large as HD 106906 to be created.
Instead, it's been hypothesised that this might have once been one its way to becoming a binary star system -- where two stars form close to each other, then begin to orbit around each other.
"It is possible that in the case of the HD 106906 system the star and planet collapsed independently from clumps of gas, but for some reason the planet's progenitor clump was starved for material and never grew large enough to ignite and become a star."
The problem with this theory, however, is that we've never observed a binary star system with a difference in mass between the two stars of more than ten-to-one. In this case, the difference is something like 100-to-one. Astronomers are now analysing more data to try to find out more.
"Systems like this one, where we have additional information about the environment in which the planet resides, have the potential to help us disentangle the various formation models," Bailey added. "Future observations of the planet's orbital motion and the primary star's debris disk may help answer that question."

Description: giant planet has been found