Astronomers have discovered an exoplanet that orbits its star every 704 days, the longest known year for an exoplanet, according to the Harvard-Smithsonian Center for Astrophysics.
Kepler 421-b orbits a star about 1,000 light years from Earth at the “frost line” – the crucial distance that divides rocky planets from gaseous planets.
At a distance of 110 million miles from its star, the planet is cold enough for little ice grains to form and stick together to form gaseous planets, said David Kipping, lead author on a paper about Kepler 421-b that will be published in The Astrophysical Journal.
Within the frost line, the ice grains “boil off, and you get something like Earth,” Kipping said.
A planet at this “special” point was expected to exist, “but we didn’t really have this evidence” before Kepler 421-b’s discovery, Kipping said.
Finding a planet like Kepler 421-b is rare.
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