Washington: NASA`s Spitzer Space Telescope has detected light emanating from a "super-Earth" planet beyond our solar system for the first time.
"Spitzer has amazed us yet again," said Bill Danchi, Spitzer program scientist at NASA Headquarters here. "The spacecraft is pioneering the study of atmospheres of distant planets and paving the way for NASA`s upcoming James Webb Space Telescope to apply a similar technique on potentially habitable planets."
The planet, called 55 Cancri e, falls into a class of planets termed super Earths, which are more massive than our home world but lighter than giant planets like Neptune. The planet is about twice as big and eight times as massive as Earth. It orbits a bright star, called 55 Cancri, in a mere 18 hours, according to a NASA statement.
Previously, Spitzer and other telescopes were able to study the planet by analyzing how the light from 55 Cancri changed as the planet passed in front of the star. In the new study, Spitzer measured how much infrared light comes from the planet itself.
The results reveal the planet is likely dark, and its sun-facing side is more than 2,000 Kelvin (3,140 degrees Fahrenheit), hot enough to melt metal. The new information is consistent with a prior theory that 55 Cancri e is a water world: a rocky core surrounded by a layer of water in a "supercritical" state where it is both liquid and gas, and topped by a blanket of steam.
"It could be very similar to Neptune, if you pulled Neptune in toward our sun and watched its atmosphere boil away," said Michaël Gillon of Universite de Liege in Belgium, principal investigator of the research, which appears in the Astrophysical Journal. Brice-Olivier Demory of the Massachusetts Institute of Technology, Cambridge, led the study.
The 55 Cancri system is relatively close to Earth, at 41 light-years away. It has five planets, with 55 Cancri e the closest to the star and tidally locked, so one side always faces the star. Spitzer discovered the sun-facing side is extremely hot, indicating the planet probably does not have a substantial atmosphere to carry the sun`s heat to the unlit side.