GJ 1214 b

System: GJ 1214

GJ 1214b orbits an M dwarf in a tight orbit, swinging the planet around every 1.6 days.

Atmospheric conditions

The planet has an atmosphere which contains higher amounts of “metals” (elements with atomic numbers higher than helium). The atmosphere is most likely at least 10% water vapor by volume. While water vapor may sound give the impression of being an inviting place for a tropical jungle, the close orbiting planet has an average temperature of a sweltering 535 degrees F.

The prevalence of such heavy elements may also give information relating to the structure and history of the planet itself. Models of planetary atmosphere suggest that, for planets of the mass and temperature expected for GJ 1214b, there are two primary formation scenarios. In the first, the atmosphere is directly accreted during the planet's formation. However, this would indicate a hydrogen rich atmosphere and has been ruled out. The second is that the planet formed further out, beyond the “snow line”, as an icy body, but moved in after formation, creating the atmosphere from sublimated ices.