How It Works

The planet swallowers

Approximately 89 light years away in the constellation Hydra is the star HD 82943. It’s the same temperature and size as our Sun, with a small system of its own comprising at least two gas giants orbiting it. A fairly standard cosmic entity then – except it has a dark past: evidence suggests HD 82943 has consumed one or more of its planets.

Scientists have detected Lithium-6 on the star’s surface and because this isotope is destroyed in the formation of a star, the most likely reason for it being there is because it is the remains of an orbiting planet. In another system 600 light years away, the hottest known planet in the Milky Way, WASP-12b, is so close to its parent star WASP-12 that it’s being heated to 1,538 degrees Celsius (2,800 degrees Fahrenheit), causing its atmosphere to expand to three times the radius of Jupiter.

Whereas HD 82943’s planets had orbits that will ultimately put them on a collision course with their star, WASP-12b is spilling material into its star at a rate that will see it utterly consumed within the next 10 million years or so