It’s only now that astronomers are officially confirming the existence of a planet orbiting KELT-9, an star about 616 light-years from Earth.
“We found [KELT-9b] back in 2014, if you can believe it,” Professor Scott Gaudi, from Ohio State University, told BBC news in a June 2017 article. “It took us this long to finally convince ourselves that this truly bizarre and unusual world was in fact a planet orbiting another star.”
KELT-9b has a daytime temperature of more than 7,800 F (4,600 K). This makes it hotter than the surface of most red dwarf stars, which are the most common type of star in the Milky Way.
The surface of KELT-9b is so hot that it is unlikely molecules can survive in its atmosphere.
“This is the hottest gas giant planet that has ever been discovered,” Gaudi said. Gaudi worked on this study with NASA’s Jet Propulsion Labratory.
“KELT-9b is 2.8 times more massive than Jupiter, but only half as dense,” according to JPL. Planets with lower density tend to have a smaller radius, but the heat from its host star has blown the planet’s atmosphere out.
The star is a blue Type-A star. At only 300 million years old, KELT-9 is a young in star years. It is more than twice as large, and almost twice as hot, as the Sun.
Keivan Stassun, a professor of physics and astronomy at Vanderbilt University, said, “KELT-9 radiates so much ultraviolet radiation that it may completely evaporate the planet.”
The JPL article states, “Given that the planet’s atmosphere is constantly blasted with high levels of ultraviolet radiation, the planet may even be shedding a tail of evaporated planetary material like a comet.”
With an orbital period of about 1.5 days and the possibility of it trailing a stream of ejected matter behind it, KELT-9b seems more like a comet than a planet. While we may not be able to learn much about alien life from this exo-planet, KELT-9b is just another example of the variety and possibility that can be found in the universe around us.