Scientists may have just managed to make the most detailed map to date of a rocky exoplanet. The new map reveals a planet that's composed of two halves, one of which is molten and the other of which is solid.
In this latest study, the researchers used information collected from NASA's Spitzer Space Telescope about a planet by the name of 55 Cancri e. This particular exoplanet orbits a sun-like star about 40 light years away from Earth in the Cancer constellation. More specifically, the researchers examined how conditions on this exoplanet changed during its orbit.
"We haven't yet found any other planet that is this small and orbits so close to its parent star, and is relatively close to us, so 55 Cancri e offers lots of possibilities," said Brice-Olivier Demory of the University Cavendish Laboratory. "We still don't know exactly what this planet is made of-it's still a riddle. These results are like adding another brick to the wall, but the exact nature of this planet is still not completely understood."
So what did the researchers find? The planet itself is tidally locked. This means that only one side of the planet faces its star. This is similar to our moon, which has a side that faces planet Earth and a side, the "dark side," that forever faces away from us. The "day" side of this new planet is actually almost completely molten. In contrast, the "night" side is almost completely solid.
Interestingly, the researchers found that the heat from the day side isn't efficiently circulated to the night side. On Earth, the atmosphere helps with the circulation of heat in order to keep the planet within a relatively narrow range, temperature wise. However, it seems that with this exoplanet, a lack of atmosphere may contribute to the lack of heat distribution.
"On the day side, the temperature is around 2500 degrees Celsius, while on the night side it's about 1100 degrees-that's a huge difference," Demory said. "We think that there could still be an atmosphere on the night side, but temperatures on the day side are so extreme that the atmosphere may have evaporated completely, meaning that heat is not being efficiently transferred, or transferred at all from the day side to the night side."
The findings reveal a bit more about this unusual planet. More specifically, it shows that a planet can at once be molten and solid at the same time.
The study was published in the March 30 issue of the journal Nature.
