A study published Wednesday revealed the existence of a system of seven planets the size of the Earth around a small star. Three of them could potentially be habitable. Astronomers have discovered the existence of a system of seven planets the size of the Earth around a dwarf star. Their study was published Wednesday, February 22 in the journal Nature. According to the researchers, three of these planets could harbor oceans of liquid water and thus potentially life.

"Now we have the right target" to look for the presence of possible life on exoplanets, said Amaury Triaud, co-author of the study.

The seven planets, which have temperatures close to those of the Earth, revolve around a very small ultra-cold star TRAPPIST-1 located in our galaxy, "only" 40 light-years away from us.

'This is the Grail for Astronomers'

"Twenty years after the first exoplanets, this is undoubtedly one of the greatest discoveries in the field of extrasolar planets," said Didier Queloz of the University of Geneva, co-author of the study. "The search for the living on another planet is now at hand," he adds.

Detection of chemical traces of life

"This is the first time that as many planets of terrestrial-size have been detected, three of which are potentially habitable, for which an in-depth study is possible with current technology, including determination of atmospheric composition and detection of chemical traces of life," said Michael Gillon, lead author of the study to a source.

Three of the planets (TRAPPIST-1 e, f, and g) are located in the "habitable" area of the system, that is, capable of housing liquid water over most of the surface. "This is the Grail for astronomers," says ESO.

Six of these planets revolve around the red dwarf in 1.5 to 12 days. They are much closer to their star than the Earth of the Sun.

The show on these planets must be "pretty beautiful", according to Amaury Triaud, also coauthor of the study. "There must be about 200 times less light than noon on Earth. This should look a bit like the end of a sunset," he said.