It seems that astronomers have made a new mind-blowing discovery as they have never seen anything similar to the planet they just detected.
KELT-9b is an exoplanet which orbits a huge star KELT-9 in the constellation Cygnus and is approximately 650 light-years away from us. It is a gas giant which completes a full circle around KELT-9 in only 1,5 days.
And finally, the most remarkable thing about the newly discovered exoplanet is that it has an incredibly high temperature on its surface.
The temperature on the day side of KELT-9b reaches 4,600 Kelvin! It is unbelievably hot and is comparable only to the surface temperature of some stars, but scientists have never seen anything like this on a planet before.
For example, our Sun reaches 5,800 Kelvin while the day-side temperature on Mercury doesn’t exceed 700 Kelvin.
How is this possible that a planet is that hot, you may ask?
It has to do with the fact that KELT-9b is located extremely close to its star, which also happens to be one of the hottest stars ever observed, with the surface temperature of 10,170 Kelvin.
Because of the extreme radiation from KELT-9, the planet is basically evaporating away, losing around 22 million pounds (10 million kilograms) of its mass per second. Since the planet is constantly blasted by its star, it also has a gas tail similar to that of comets.
Because of these processes, it is estimated that KELT-9b won’t be there for long and will either completely evaporate away or will be boiled down to its solid core (if it has one, because scientists don’t know for sure).
“KELT-9 radiates so much ultraviolet radiation that it may completely evaporate the planet. Or, if gas giant planets like KELT-9b possess solid rocky cores as some theories suggest, the planet may be boiled down to a barren rock, like Mercury,” Keivan Stassun, Professor of Physics and Astronomy at Vanderbilt University, said in a press release.
The only thing that is clear for now is that the newly discovered planet doesn’t have bright prospects for the future. It is estimated that KELT-9 will begin to expand and will become a red giant in around a billion years. So if its radiation doesn’t evaporate KELT-9b till then, then the massive star will probably just swallow it.
What else do we know about the unusually hot exoplanet?
KELT-9b is a gas giant which is 2,8 times more massive than our Jupiter. At the same time, it is only half as dense due to the harsh ultraviolet radiation from its star.
Such unfavorable conditions make it impossible for molecules of water, methane and carbon dioxide to form, so it makes sense why the planet just can’t maintain an atmosphere.
“It’s a planet by any of the typical definitions based on mass, but its atmosphere is almost certainly unlike any other planet we’ve ever seen just because of the temperature of its day side,” said Professor Scott Gaudi, one of the study’s lead authors.
This exciting discovery, the results of which were reported in the journal Nature, demonstrates once again how little we actually know about our universe and how many fascinating things we are yet to learn about our cosmic neighborhood.