The exoplanet with a ‘year’ that lasts 8½ hours
A planet outside our solar system zips around its star in roughly the same time as a good night’s sleep on Earth
Earth-sized exoplanet named Kepler 78b, which whips around its host star in less than nine hours – one of the shortest orbital periods ever detected
If you’ve ever felt like the years are flying by, then you might identify with exoplanets that complete their “year” in just a few hours.
An exoplanet (or planet that lies outside our solar system) called Kepler 78b, described by MIT researchers in the Astrophysical Journal, completes its orbital circuit every 8½ hours, zipping around its star in roughly the same time as a working day or a good night’s sleep on Earth.
But while it might permanently feel like New Year’s Eve on Kepler 78b, the exoplanet would be no place to hold a party: its closeness to the star probably means the planet’s surface is a toasty 2,750 degrees or so, and its surface is likely molten, according to a release from MIT.
“You’d have to really stretch your imagination to imagine living on a lava world,” says researcher Josh Winn. “We certainly wouldn’t survive there.”
Another fleet exoplanet, KOI 1843.03, analysed by MIT researchers and others in the Astrophysical Journal Letters, rounds its star in an even more speedy 4.2 hours. “Just the fact that it’s able to survive there implies that it’s very dense,” says Winn, a co-author on both papers. “Whether nature actually makes planets that are dense enough to survive even closer in, that’s an open question, and would be even more amazing.”
Dr Niall Smith from Blackrock Castle Observatory and Cork Institute of Technology, who was not involved in the study, says the findings are fascinating. “As we find increasingly exotic planets, we realise our understanding of planetary formation is really at an early stage,” he says. “Who knows what we might find next?”