NASA’s TESS satellite recently identified three new exoplanets 35 light years from Earth. One of them, L 98-59b, is the smallest ever discovered by the telescope.
Kepler retired, it is now TESS (Transiting Exoplanet Survey Satellite), NASA’s new exoplanet hunter, who has taken the thrown. Placed in orbit last April, the telescope aims to detect the presence of new worlds evolving around 200,000 nearby stars. Some exoplanets have so far been detected, including a earth-like world spotted a few weeks ago about 52 light-years from Earth.
However, a few days ago, NASA announced that it had identified three new worlds. Closer, this time, about 35 light-years away. Unfortunately, none evolves in the habitable zone of its star.
The host star, L 98-59, is a red dwarf. It is about a third of the Sun’s mass, and seems to be 70% cooler. Around it evolve three planets. L 98-59b is the one that most interests astronomers, in the sense that it is the smallest world ever discovered by TESS (80% of the size of the Earth). This is not the smallest world ever discovered. This honor goes to Kepler-37b, barely larger than the Moon. The other two exoplanets in the system, L 98-59c and L 98-59d, are respectively 1.4 and 1.6 times the size of the Earth.
Regarding the potential of life, no need to look for long. None of these worlds actually evolves in the habitable zone of its star. L 98-59b, for example, goes around every 2.25 days and receives up to 22 times more energy than Earth receives from the Sun. L 98-59c orbits the star every 3.7 days and receives 11 times more radiation than the Earth. L 98-59d is the farthest (7.5 days), but still receives four times as much radiation as our planet.
These three exoplanets were identified thanks to the transit method. It consists in detecting periodic hollows of luminosity of the host star. We do not know much yet about them. More in-depth studies from the ground could nevertheless determine whether an atmosphere is present or not. Scientists could too, if necessary, analyze their composition. But in view of their orbit, it is very likely that these worlds are similar to a planet like Venus in our system.