A team of international astronomers, including those in Switzerland, have discovered a rocky exoplanet in a habitable zone of a faint red dwarf star.
The super-Earth LHS 1140 is in the constellation of Cetus about 40 light-years from Earth, according to the European Southern Observatory (ESO).
Scientists describe the exoplanet as the “best place to look for signs of life beyond the solar system”, according to a press release on Wednesday.
“We could hardly hope for a better target to perform one of the biggest quests in science: searching for evidence of life,” said Jason Dittmann of the Harvard Smithsonian Center for Astrophysics.
Nicola Astudillo-Defru from Geneva Observatory says the present conditions of the red dwarf are particularly favourable and LHS 1140 spins more slowly and emits less high-energy radiation than other similar low-mass stars.
Geneva University says its HARPS planet searcher instrument was key in confirming the presence of the super-Earth.
The astronomers estimate the age of the planet to be at least five billion years and that it is 1.4 times larger and seven times more dense than Earth. They deduce that the exoplanet is probably made of rock with a dense iron core.
It has likely retained most of its atmosphere and passes in front of its parent star as it orbits, blocking a little of its light every 25 days.
“This super-Earth may be the best candidate yet for future observations to study and characterise its atmosphere, if one exists,” according to ESO.
A super-Earth is an extrasolar planet with a mass higher than Earth’s, but substantially below the masses of the Solar System’s giants, Uranus and Neptune, which contain 15 and 17 Earth masses respectively.
The full results of the discovery will be published by the journal Nature on Thursday.
ESO is supported by 16 European states, including Switzerland, and operates three observation sites in Chile.