Astronomers have discovered a gigantic planet orbiting a puny star some 30 light-years away. And according to current theories, the planet shouldn’t exist. Dubbed GJ 3512 b, the gas giant is at least half the mass of Jupiter. But it orbits a red dwarf star that’s just one-tenth the mass of our Sun.

"Around such stars there should only be planets the size of the Earth or somewhat more massive Super-Earths," said Christoph Mordasini of the University of Bern in a press release. "GJ 3512 b, however, is … at least one order of magnitude more massive than the planets predicted by theoretical models for such small stars."

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Scientists thought that gas giants like Jupiter always started their lives by developing heavy, solid cores before quickly accumulating thick, gassy atmospheres. That’s what current models predict. But because of this new planet’s unusual heft compared to its host star, the new research suggests that’s not always the case.