A discovery released on Thursday (5) by an international team of astronomers could represent an important step in the search for life on planets the size of ours, outside the Solar System. According to the researchers, orbiting the star L 98-59, 35 light-years from Earth, there is a supposed oceanic world that may have habitable conditions for Earth humans.
Co-author of the study, Spanish María Rosa Zapatero Osorio, an astronomer at the Center for Astrobiology in Madrid, Spain, guarantees that “the planet in the habitable zone may have an atmosphere that could protect and sustain life.” Published in the scientific journal Astronomy & Astrophysics, the discovery was made from the Very Large Telescope (VLT), of the European Southern Observatory (ESO’s VLT), in Chile.
Using the VLT spectrograph, astronomers observed a planetary system, with a possible habitable zone, orbiting a bright M dwarf star. Called L 98-59, “this system is destined to become a cornerstone for comparative exoplanetology of terrestrial planets,” the study says.
What is the L 98-59 Planetary System like?
Comparison between the L 98-59 system and our Solar System (Source: L. Calçada/M. Kornmesser/ESO/Disclosure)Source: L. Calçada/M. Kornmesser/ESO
The L 98-59 planetary system is possibly made up of five planets, three of which are rocky and may contain water in their interior or atmosphere. The two planets closest to the star are likely dry, although they may contain small amounts of water, but the third planet may have water on up to 30% of its surface, making it an oceanic world.
In addition to these celestial bodies, the team detected other “hidden” exoplanets, that is, ones that had not been previously observed in this planetary system. They suspect the existence of a fourth and a fifth planet, at a distance from the star compatible with the existence of liquid water, or, as astronomer Olivier Demangeon explains, a habitable planet in this system.
The article’s first author, Demangeon, who is a researcher at the Faculty of Sciences of the University of Porto, Portugal, said in a statement that “we are finally getting closer and closer to detecting a terrestrial planet in the habitable zone of its star , from which we can study the atmosphere”,
The new study represents extraordinary technical progress, as astronomers have managed, through the method that uses radial velocity, to claim that the innermost planet of the L 98-59 system has half the mass of the planet Venus. This makes this exoplanet the lightest gravitational body ever measured using this type of technique, which observes the star’s oscillation based on minimal variations of the planets.
The research also made it possible to use a new instrument, the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO), for the first time on the ESO VLT, to study the L 98-59 system. “Without the precision and stability of ESPRESSO, this measurement would not have been possible”, says Zapatero Osorio. It was the use of the device that allowed the measurement of masses of smaller exoplanets.
James Webb Telescope (Source: ESA/Disclosure)Source: ESA
The team responsible for the discoveries says it intends to deepen the observation of planets in the L 98-59 system, especially their atmospheres, in search of traces of life.
This should be done with the James Webb telescope, which is scheduled to be launched into space later this year. They will also use the European Extremely Large Telescope (ELT), with a mirror measuring 39 meters in diameter, currently under construction in Chile’s Atacama Desert.
ARTICLE Astronomy & Astrophysics: doi.org/10.1051/0004-6361/202140728