After determining the mass of Pi Mensae c, astronomers realized that the planet is likely more similar to an extremely small variant of Neptune rather than a very large variant of Earth. But within a few days of announcing their first planet, the TESS team had already found their second—and it’s a really weird one.


The planet orbits the star LHS 3844, which is a cool, small star called a red dwarf. These cool little stars represent the most plentiful type of star in the universe. Many red dwarfs have planets that orbit in a matter of days, but the newly discovered planet around LHS 3844 completes its orbit in just 11 hours. One week on Earth accounts for 15 “years” on this planet, putting it into a small class of ultra-short period planets.


At first, TESS discoveries will be biased toward these kinds of planets—repeated transits across the star mean they’re easier to detect. With dozens of strong candidates still on the TESS list for this sector, there could be plenty of discoveries right around the corner. Such collateral planets will pile up during the mission while we wait to discover more Earth-like worlds that orbit their stars in a few hundred days.


But as Burt points out, even the inhospitable planets paint a brilliant story of the night sky. The star Pi Mensae, now with two known planets, is bright enough to see with the naked eye. When TESS’ initial two-year mission is up—and the team is already planning a mission extension—we should have a good understanding of which nearby stars have orbiting worlds of their own.


“By the time TESS finishes its mission, you should be able to walk out into your backyard, point at a star, and know there are planets around it,” Burt says. Perhaps one of those planets will even look a bit like our own.