A Jupiter-sized planet much hotter than most stars and with a gigantic, glowing tail of gas like a comet. This is the new exoplanet discovered by a team of international astronomers led by the Ohio State and Vanderbilt universities (USA) and which is collected by the journal Nature.
The planet found thanks to the observations of the KELT-North telescope at the Winer Observatory in Arizona and named KELT-9b, orbits a massive star located 650 light years from Earth in the constellation Cygnus . It is one of the few stars discovered around a type A star, which oscillates between such colossal temperatures: 7,026 and 9,726 degrees Celsius.
During the day, the planet’s maximum temperature is 4,300 ° C (the highest temperature among all known planets so far) and the ultraviolet radiation from the orbiting star is so brutal that it can literally cause the planet to evaporate, producing a tail of glowing gas .like a comet. And it is that its star (type A) is 2.5 times larger and almost twice as hot as our Sun.
The super-hot planet has other unusual characteristics as well: it has a 1.5-day orbit and is a gas giant 2.8 times more massive than Jupiter but at half the density, as extreme radiation from its host star has caused it to its atmosphere swells like a balloon.
The situation of both is like that of the Moon to the Earth, so the day side of the planet is permanently bombarded by stellar radiation and, as a result, it is so hot that the molecules of water, carbon dioxide or methane cannot. train there.
“It is a planet by any of the typical mass-based definitions, but its atmosphere is unlike any other planet we’ve seen just because of the temperature on its side of the day,” says Scott Gaudi, co-author of the paper.
The future of KELT-9
The planet’s orbit is very close to the star, so if the star starts to expand, it will engulf it. “ KELT-9 will swell to become a red giant star in about 1 billion years, ” says study co-author While Stassun.
Reference: B. Scott Gaudi et al, A giant planet undergoing extreme-ultraviolet irradiation by its hot massive-star host, Nature (2017). DOI: 10.1038 / nature22392
