Every year the planet gets closer to its star
The first planet observed by the Kepler space telescope falls into its star.
Kepler launched a mission in 2009 to search for exoplanets, watching them cross in front of their stars. The first potential planet spotted by the telescope was initially dismissed as a false alarm, but in 2019 astronomer Ashley Chontos and colleagues proved that it is real. The planet was officially named Kepler 1658b.
Now Chontos and others have determined the fate of Kepler 1658b. “He’s tragically becoming a major star,” says Chontos, who is now at Princeton University. The planet has about 2.5 million years left before it faces a fiery death. “Eventually it will be absorbed. Death by a star.”
The roughly Jupiter-sized planet is very hot, orbiting its star once every three days. In follow-up observations from 2019 to 2022, the planet continued to orbit the star earlier than expected.
Combined data from Kepler and other telescopes show that the planet approaches the star Chontos and his colleagues reported on December 19 Astrophysical Journal Letters .
“You see the interval between transits shrinking, very slowly but very steadily, at a rate of 131 milliseconds per year,” says astrophysicist Shreyas Vissapragada of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
It doesn’t sound like much. But if this trend continues, the planet will have only 2-3 million years to live. “For something that existed 2-3 billions years, that’s quite a few,” says Vissapragada. If the life expectancy of the planet were more than 100 human years, it would have a little more than a month left.
Studying Kepler 1658b at the time of its death will help explain the life cycles of similar planets. “By learning something about the actual physics of how orbits shrink over time, we can better understand the fates of all these planets,” says Vissapragada.
