Hottest ever known planet found with temperature of 4,327ÂºC
NASA has discovered the hottest planet in the known universe, with a surface temperature of over 4,327ÂºC. The Jupiter-like giant KELT-9b, which is nearly as hot as the Sun, is tidally locked with its host star, meaning the planet's one side is always facing the star. Researchers further said the host star is even hotter and is vapourising the planet.