NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered a world between the sizes of Mars and Earth orbiting a bright, cool, nearby star. The planet, called L 98-59b which is the tiniest exoplanet discovered by TESS to date.
L 98-59b has some company: two other planets also circle the same star. Each planet’s size is unknown at this time and additional telescope observations will be needed to determine which gases are present on their surfaces and if they have atmospheres, NASA said in a press release. A paper on TESS’ L 98-59b discovery, which was published in The Astronomical Journal on June 27, details findings on the three planets, which could help scientists analyze other similar exoplanet systems in the future.
However, the researchers wrote, “This system is especially interesting because the planets are orbiting such a bright star that it will allow TESS to gather an unusual amount of data from them. Close measurements of their orbits might enable scientists to figure out whether there are other planets in the system tugging on them with gravity — perhaps even planets in that star’s habitable zone. That could offer valuable data about how small, rocky planets like ours form. Researchers also hope to learn whether the planets have atmospheres, based on how they add color to the light coming from the star as they pass in front of it.”
“If you have more than one planet orbiting in a system, they can gravitationally interact with each other,” said Jonathan Brande, a co-author and astrophysicist at Goddard and the University of Maryland, College Park. “TESS will observe L 98-59 in enough sectors that it may be able to detect planets with orbits around 100 days. But if we get really lucky, we might see the gravitational effects of undiscovered planets on the ones we currently know.”