Once upon a time, GJ 1132 b was a smallish gas giant planet. Then powerful radiation from its parent star burned off its massive envelope of gas, leaving behind only a desiccated rocky core — a super-Earth, about 1.6 times the mass of our planet.
Now, a group led by researchers at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena has analyzed Hubble Space Telescope observations of GJ 1132 b and found something very peculiar: the planet seems to have reestablished an atmosphere. Furthermore, the composition of the gases suggests a volcanic origin.
Based on what we know of our own solar system, full atmospheric makeovers on rocky planets are not uncommon. Earth’s atmosphere has been completely remade twice — first by volcanic activity and meteorite impacts, and then by the emergence of life. Mars is on its second or third atmosphere. But this is the first time that a secondary atmosphere has been reported on an exoplanet.
Some researchers think the detection is more tentative than the team claims. But if it stands, it could have wider implications for theories of planetary formation — and demonstrate that studying exoplanet atmospheres can also offer insight into what happens below the surface.
