Ultrahot Jupiter Discovered With 16-hour Orbit

A newly discovered gas giant five times the mass of Jupiter was found orbiting its star in 16 Earth hours as it spirals in toward its eventual demise.

IMAGE: The newly discovered planet is relatively close to its star, at a distance of only about 1.5 million miles out. CREDIT: NASA, ESA and G. Bacon

A newly discovered exoplanet has provided an extreme case of an ultrahot Jupiter. Because we needed more ways to compare exoplanets to Jupiter, I guess.

Found using data from NASA’s TESS spacecraft and reported in The Astronomical Journal, exoplanet TOI-2109b has dayside temperatures estimated to be about 3,500 Kelvin or 3,200˚ Celsius. That makes this gas giant as hot as a small star and the second hottest planet ever discovered. The hottest exoplanet? Dr. Pamela’s favorite, KELT-9b, comes in at a vaporizing 4,300 degrees Celsius.

Of course, one of the defining characteristics of hot Jupiters is the length of their orbit, which is generally less than ten Earth-days because these worlds are incredibly close to their parent stars. TOI-2109b is no exception and in fact, has the shortest known orbit at just 16 Earth hours. Hours. Not days but hours. Oof. I cannot imagine the speed of the winds on that world. And in addition to being super fast, super close, and super hot, this gas giant is about five times the mass of Jupiter.