WASHINGTON • A frozen and slightly illuminated planet, known as "Super Earth", can be the nearest single star to our solar system, astronomers said Wednesday based on two decades of scientific observations.
The planet, estimated to be at least 3.2 times more massive than the Earth, was discovered around Barnard's Star, a kind of relatively cool and low-mass star called a red dwarf, about six light years from our solar system, relatively close to cosmic conditions. It is believed to traverse Barnard Star every 233 days.
Planets that circle stars beyond our solar system are called exoplanets. Nearly 4000 have been discovered.
The newly discovered is the second closest to our solar system ever found. It is considered a super-earth, a category of planets that are more massive than the Earth but less than the big gasplanets.
"After a very careful analysis, we are 99 percent convinced that the planet is there," said researcher Ignasi Ribas of the Institute of Space Studies in Catalonia and the Space Research Institute in a statement.
"But we continue to observe this fast star to rule out possible but unlikely, natural variations of the star-shaped brightness that can mask like a planet."
The only closer to the Stars than the Barnard Star are part of the triple star Alpha Centauri system, which lies a little more than four light years from our solar system. Two years ago, astronomers announced the discovery of an approximately earthy planet circulating Proxima Centauri, a part of the Alpha Centauri system, in a circulation that allows liquid water to be found on its surface, increasing the possibility that it could trigger alien life.
The number of days it's supposed to take the planet to run Barnard's Star.
The newly discovered planet's circling Barnard Star can not be so hospitable, with surface temperatures of maybe minus 170 degrees C.
Barnard Star gives the free planet just 2 percent of the energy the sun gives to the earth.
The researchers studied the planet by combining measurements from several high precision instruments mounted on telescopes around the world. The research was published in the journal Nature.