Astronomers have found what could very well be a new class of exoplanet: the "Mega-Earth." Using the Kepler space satellites, scientists have found Kepler-10c, a giant rocky planet 17 times more massive than the Earth.
Most scientists previously thought that massive planets often form as gas giants similar to Jupiter, Saturn or Neptune. Massive planets often accumulate hydrogen, which results in the formation of large and massive gas planets. However, the discovery of Kepler-10c indicates that massive, solid planets are also possible. While rocky planets much larger than Earth have been found in the past, Kepler-10c is unlike anything the world has seen so far. Unlike "Super-Earths," the new "Mega-Earth" is far larger and more massive than the Earth being twice the size and 17 times more massive.
"We were very surprised when we realized what we had found," said Harvard-Smithsonian Center for Astrophysics (CfA) astronomer Xavier Dumusque. Dumusque is also the lead scientist of the team that discovered the new "Mega-Earth."
After confirming the discovery, the team announced their findings at the American Astronomical Society (AAS) meeting.
"This is the Godzilla of Earths!" said Dimitar Sasselov, also a researcher from the CfA. "But unlike the movie monster, Kepler-10c has positive implications for life."
Due to the fact that the planet is solid, scientists believe that it may have an atmosphere that may be capable of supporting life. Many rocky planets often lose their atmospheres gradually as time passes. Due to the mass of the newfound planet however, the possibility of maintaining an atmosphere remains.
"Kepler-10c didn't lose its atmosphere over time. It's massive enough to have held onto one if it ever had it," added Dumusque. "It must have formed the way we see it now."
The team was able to find the planet using the Kepler space observatory, which uses gravitational lensing to look for exoplanets in distant stars. By looking for the telltale lensing effect caused by a planet travelling in front of its star, scientists can find exoplanets. Studying the effects of gravitational lensing can also reveal important details about an exoplanet such as its composition. After Kepler spotted the planet, the team then used the HARPS-North instrument located in the Canary Islands to determine the approximate mass of the planet.
Kepler-10c is estimated to be around 2.3 times larger than earth with a diameter of approximately 18,000 miles.
"Finding Kepler-10c tells us that rocky planets could form much earlier than we thought. And if you can make rocks, you can make life," Sasselov said.
