If you’re sweating from our current heat wave, be glad you don’t live on planet KELT-9, orbiting a blue A-type star 620 light years from Earth.
KELT9b is the hottest gas giant planet ever found, with a surface temperature of 7,800 degrees Fahrenheit; hotter than most stars!
KELT-9 is tidally locked so that one side is literally boiling – the UV radiation is so intense that heavier molecules like water, CO2, or methane can’t form. The star itself is twice as large and twice as hot as our sun – over 20,000 degrees Fahrenheit. The blast from the sun is so intense, the gas of the gas giant is probably being blown away – evaporated or vaporized! At 300 million years old, the star is quite young, EXCEPT it is a Blue type A – it won’t last long at all.
On the opposite end of the spectrum, a planet at TRAPPIST-1, h, is far enough away from its too-cool star (6 million miles) that its surface temperature is -148 degrees Fahrenheit.
Saturn’s got the swing shift! Jupiter, then Saturn by 10p, by 4:30 a, Saturn in the west and Venus in the east – Saturn’s the planetary pivot of the sky! Anybody notice last week’s mini-moon? Didn’t think so… the difference in size was too small to notice!