Astronomers find hottest giant planet

Washington: Astronomers have discovered the hottest planet ever known, with a dayside temperature of more than 4,300 degrees Celsius.In fact, this planet, called KELT-9b, is hotter than most stars, according to a study published in the journal Nature.

"This is the hottest gas giant planet that has ever been discovered," said Scott Gaudi, Professor at the Ohio State University in Columbus who led a study. KELT-9b is 2.8 times more massive than Jupiter, but only half as dense. It is nowhere close to habitable, but Gaudi said there is a good reason to study worlds that are unlivable in the extreme.

"As has been highlighted by the recent discoveries from the MEarth collaboration, the planet around Proxima Centauri, and the astonishing system discovered around TRAPPIST-1, the astronomical community is clearly focused on finding Earthlike planets around small, cooler stars like our sun," Gaudi said.

"They are easy targets and there's a lot that can be learned about potentially habitable planets orbiting very low-mass stars in general. On the other hand, because KELT-9b's host star is bigger and hotter than the Sun, it complements those efforts and provides a kind of touchstone for understanding how planetary systems form around hot, massive stars," he explained.