A gigantic planet that “shouldn’t exist” is baffling scientists. Located 31 light-years away from Earth is a large gas planet called GJ 3512b. What’s so strange about the planet is that it’s approximately half the size of Jupiter and it orbits a star that’s eight times smaller than our own Sun.
Planets that huge are already quite rare, but to orbit such a small star makes this planet an even bigger mystery. In fact, it’s so large that it couldn’t have been born the same way that other planets form. Scientists from Switzerland, Spain, and Germany are left completely baffled as to how GJ 3512b was formed and could ultimately cause astronomers to re-evaluate how all planets are born.
Professor Christoph Mordasini, who is a scientist at the University of Bern, explained, “Around such stars there should only be planets the size of the Earth or somewhat more massive Super-Earths,” adding, “GJ 3512b, however, is a giant planet with a mass about half as big as Jupiter’s.”
The planet, which is made up of gas and dust, was discovered by space scientists who were using a telescope at the Calar Alto Observatory in the southern part of Spain. It orbits its tiny red dwarf star every 204 days.
Ordinarily, planets form when rocks and dust combine together by a star’s gravitational pull. The planets continue to grow until they are big enough to retain their own atmospheric gas. However, studies conducted by the scientific team indicate that GJ 3512b couldn’t have been born in that manner because its star is way too small to have the gravitational pull that would have been required for the planet to form.
The team said that after a disc of rock and dust that was orbiting the star had “collapsed under its own gravity”, that’s probably when the planet began forming. It was previously thought that the type of planet formation called gravitational instability had been a rare occurrence, but scientists now think that it’s actually not that uncommon. You can read their entire study in the journal Science.
Juan Carlos Morales, who is an astronomer at the Autonomous University of Barcelona, and was involved with the discovery, told New Scientist, “This is the first time that we have a clear detection of a planet where the only possible way to explain it is gravitational instability.”
With more than 4,000 exoplanets discovered so far, it’s very likely that scientists will find more unusual planets like GJ 3512b.