Volcanic Super-Earth

Huge surface temperature changes have been detected by Cambridge scientists on a 'super-Earth' light years away - which could be the first record of volcanic activity on these bodies.

A super-Earth is a planet found outside of our solar system with a mass equivalent to up to ten times greater than the mass of our Earth. These planets are intensively studied to help give us clues about our own origins and early formation. The planet in question, 55 Cancri e, is one of the closest and smallest super-Earths; orbiting a star only 40 light years away and just under twice the diameter of the Earth. It does not rotate as we do, but instead has sides fixed facing to or away from the star, and is so close to it that a year - 365 days for us - lasts only 18 hours. Based on its size, mass and density, two theories were proposed: that this planet was either water based or carbon based. However, the new evidence from thermal emissions has entirely changed these ideas."We have to completely reinterpret what we thought of this planet" says Brice-Olivier Demory, lead author of the study. Thermal data was collected using NASA's infra-red Spitzer Space Telescope. By observing the light received before and after the planet was eclipsed by its star, the percentage of light from the planet could be calculated, and subsequently its surface temperature. It was shown to change rapidly and significantly, moving between 1000 and 2700 degrees Celsius on the fixed 'day side'. This dramatic variation is likely due to volcanic surface activity emitting large clouds of gas and dust, which prevent thermal emission being registered here on Earth. Further tests are needed to fully confirm the presence of volcanoes, but if they can exist on a super-Earth then our understanding of volcanism will be significantly altered. "The possibility of having volcanic activity on planets larger than Earth is currently debated." Demory explains. "This research therefore has important conclusions regarding how volcanism and plate tectonics can exist on larger bodies."