A giant planet circling a tiny star 31 light-years from Earth has puzzled astronomers – because it should not actually exist.
The world of gas is half the size of Jupiter and still vibrates around a star that is eight times smaller than our star Sun.
Planets of this size are extremely rare, especially around small stars.
The newly discovered world, called GJ 3512b, is so big that it can not have formed as we expect it to do on most planets The team of Swiss, Spanish and German scientists who scratched their heads.
The discovery may force astronomers to rethink planet formation, researchers said.
"Around such stars there should only be planets the size of the planet Earth or something more massive super-earth," said Professor Christoph Mordasini, a scientist at the University of Bern.
"However, GJ 3512b is a giant planet with a mass about half that of Jupiter. It is at least an order of magnitude heavier than the planets predicted by theoretical models for such small stars. "
Space scientists found the mysterious world with a telescope at the Calar Alto Observatory in southern Spain.
GJ 3512b is a A huge amount of gas and dust that circles its star every 204 days.
It is 31 light-years from Earth, which means that it is relatively close in space.
All in all, she is fairly unremarkable until compared to her, his host, a small, weak star known as the Red Dwarf.
GJ 3512b is at least 46 percent as massive as Jupiter, but orbits a star that is 12 percent of the Sun's mass.
For comparison: Our Sun is about 1,050 times the size of Jupiter, GJ 3512 is only about 250 times larger than GJ 3512b.
Planets normally form when dust and rocks connect due to the gravitational force of a star.
The watt gets bigger and bigger until it's big enough to hold it's own gas atmosphere.
However, the team's simulations suggest that GJ 3512b could not have formed in this way.
Its star is just too small to have the gravitational force required to form GJ 3512b.
Instead, the planet was probably born after a disk of dust and rock circling the dwarf star collapsed under its own gravity, scientists said.
This unusual form of planet formation, called gravitational instability, has been considered rare, but the find suggests it occurs more often than we thought.
"This is the first time that we can unequivocally identify a planet, with the only explanation being gravitational instability." Juan Carlos Morales, astronomer at the Autonomous University of Barcelona Also involved in the discovery, New Scientist said ,
The study was published in the journal Science.