Potentially habitable planet found in new solar system

An international team of astronomers has discovered a new solar system with a planet that could be habitable, a Spanish astrophysicist who led the research said yesterday. Three new planets were discovered orbiting GJ 357, a red dwarf -- a small and cooling star -- 31 light years away, relatively close in space terms, said Rafael Luque of Spain’s Institute of Astrophysics in the Canary Islands.

The discovery was also reported by NASA, whose TESS planet-hunting satellite made it possible. The planet known as GJ 357d -- the furthest away from the star -- was particularly intriguing as researchers estimate it could be habitable. The other two are deemed too hot. Signs of habitability in any planet include a rocky terrain, a size similar to Earth and a distance from their sun -- the temperate “Goldilocks” zone neither too close nor too far -- that allows the right temperature for liquid water, a key requirement for life.

Given its distance from its star, similar to that of Mars to our Sun, researchers estimate the planet has temperatures of -53 degrees Celsius (-63.4 Fahrenheit), Luque said. “That seems a little cold at first,” he said. But “if this planet had an atmosphere (unlike Mars), it could retain the heat it receives from its star, and water could be liquid.”