The Tess satellite has just discovered three rocky planets orbiting a star close to our Solar System. One of them is the smallest in almost a year of exoplanet hunting.
It has been a year since Tess (Transiting Exoplanet Survey Satellite), a satellite stationed in the suburbs of the Earth, began its hunt for exoplanets. In particular, the search for worlds close to us, in a radius of 300 light-years, and as far as possible that resemble us.
Some planets have been flushed out and the last shot is a trio of rocky planets in orbit around a red dwarf in the constellation Southern of Fish Wheel, the star L 98-59, only 35 light years from Earth. Although they do not appear in the habitable zone of their star-host but in the so-called Venus zone, L 98-59b, L 98-59c and L 98-59d appear particularly interesting for astronomers because of their relative proximity with our Solar System and their regular transits in front of their star make possible the characterization of their atmosphere if, of course, they have one.
The smallest exoplanet discovered by Tess
Tess’s observations, via the transit method, revealed that they have sizes close to those of the Earth. The nearest, L 98-59b, is even the smallest exoplanet discovered to date by the satellite. With an estimated size of 80% that of our blue planet, she received throughout her year of 2.25 days, about 22 times more energy from its star that we the sun.
The next, L 98-59c, almost one and a half times larger than our planet, receives 11 times more on the 3.7 days of its orbital period. As for L 98-59d, the farthest known to date in this system, has four times more energy in its year.
The latter interests researchers because it could have a “profile” similar to our charming Venus. Why did it go so bad? The researchers do not explain it well, but could find answers elsewhere.
“If we could see the sun from L 98-59, the passages of the Earth and Venus would make us think that the planets are nearly identical and, as we know, they are not,” the researchers noted. “We still have many questions about why Earth became habitable and not Venus. If we can find and study similar examples around other stars like L 98-59, we could eventually reveal some of its secrets.”