Recently, a new new planet was discovered, & it's the hottest of any known.
https://www.somagnews.com/planet-breaks-hydrogen-molecules-atmosphere-warmth/The star KELT-9, discovered by the Kilodegree Extremely Little Telescope, which has a mass of 2.5 Suns & 2.4x its radius, is known to have a surface temperature of 10,170K. Not only much hotter than our Sun, but so hot that its planet, KELT-9b, has a boiling surface temperature averaging a whopping 4,300 degrees K.
Its atmosphere's so hot refractory elements normally sequestered into molecules can exist as atomic species, including neutral & singly ionized atomic iron & titanium.
Molecules in general, including hydrogen gas, are unstable on the planet's hot day side & are broken into their component atoms, only to temporarily reform once they reach its ever so slightly cooler night side.
Here's a simulation made of the system consisting of the star & its planet.
The star's temperature is slightly off due to a temperature-changing bug that drops/rises a star's temperature & mass out of proportions when manually changing the temperature in even the slightest.
I set the radius to 2.4 suns & 2.5 suns, which magically put the temperature to 10,878K (extremely close to the real thing).
The system will be modified once the bug's addressed.