CoRoT-7b is so close to its parent star – and so hot – that scientists think it could be the remnant of an evaporated ‘hot Jupiter.’
Astronomers appear to have caught an exoplanet – a planet orbiting another star – in the middle of a cosmic vanishing act.
The planet, tagged CoRoT-7b, first hit the headlines last September when a team of astronomers confirmed the orb as the smallest exoplanet yet found. Its diameter is roughly 1.7 times that of Earth. Based on its size and mass, its density is similar to Earth's, indicating that it is a rocky Earth-like orb.
But it wasn’t always this small. Scientists estimate that CoRoT-7b initially tipped the cosmic scales at 100 times more mass than Earth and orbited the star at a distance of about 2.3 million miles.
New findings suggest its proximity to its sun gives it a molten-hot surface temperature that is causing the planet to slowly vaporize.
If the astronomers’ calculations are correct, the planet could be the first of a new class of planets, which astronomers have dubbed “evaporated remnant cores.”
CoRoT-7b orbits so close to its parent star – some 1.6 million miles away, compared with 93 million miles for Earth – that its "year" lasts 20.4 Earth hours. That gives it a surface temperature of some 3,600 degrees Fahrenheit on the daylit half. Such searing temperatures translate into a roiling surface of molten rock.
Many of the expolanets found at similar or somewhat larger distances from their suns have been so-called hot Jupiters – slowly roasting gas-giant planets. Having a rocky, Earth-sized planet in a similar orbit raises the question: Could CoRoT-7b be the remains of a vaporized hot Jupiter?