A new planet is added to the still limited list of good candidates for the search for signs of life beyond the solar system, announced Wednesday the European Southern Observatory (ESO).
The latter, named Ross 128b, was discovered around a star in the constellation Virgo, located just 11 light years from the Solar System (a light year equals 9.460 billion km) of the Earth.
“Ross 128b is very close, which will allow us to see it with a telescope such as the E-ELT under construction for 2025”, explains AFP Xavier Bonfils, astronomer CNRS at the Observatory of Science of the Grenoble Universe.
Detected by the HARPS spectrograph, installed on the ESO telescope of 3.6 meters in Chile, the planet orbits around a dwarf star (Ross 128) in 9.9 days.
According to the researchers, Ross 128b is likely to harbor signs of life: it has a mass similar to that of the Earth (1.35 more massive) and “its surface temperature could also be close to that of the Earth”, so can -be compatible with the presence of water in the liquid state essential to life as we know it.
In addition, this new planet orbits around a star “calm”, its atmosphere has a chance to have resisted the winds and stellar eruptions.
Xavier Bonfils’ team is eagerly awaiting the commissioning of ESO’s European Extremely Large Telescope (E-ELT), under construction in Chile, to study Ross 128b more precisely and to discover if it has is an atmosphere and if the density of the latter is sufficient to protect the planet from its star (including X-rays).
The presence of an atmosphere represents “the great unknown for all the exo-Terres (exoplanets whose mass is close to that of the Earth, ed) detected today”, notes Xavier Bonfils A mystery which, for the candidate planets the least distant from the Earth, could be raised with the next arrival of a new generation of telescopes.
Then, will remain to define if this atmosphere contains traces of dioxygen, water or methane, closely related to life.
Ross 128b represents the closest temperate exo-Earth to us after Proxima b, whose announcement of the discovery made a big noise in August 2016. This exoplanet was flown in orbit around the star Proxima Centauri, distant of 4.2 light-years by making a neighbor on the scale of the Universe.
Of the thousands of exoplanets detected so far, about fifty are considered potentially habitable.