The hottest known exoplanet is back in the news, answering some questions about ultra-hot planets, while also raising some new ones.
The planet, KELT-9b, was first announced in 2017. It’s roughly three times the mass of Jupiter, orbits its star every day and a half, and is a whopping 7,800 degrees Fahrenheit (4,300 Celsius). Just for the record, that’s hotter than some stars. And according to new research, the planet's dayside is also hot enough to tear apart hydrogen molecules, which astronomers recently observed.
Turn to heat evenly
Researchers, including Megan Mansfield from the University of Chicago, sought to understand how heat is distributed on this faraway world. So they watched carefully with the powerful (and soon to be decommissioned) Spitzer Space Telescope.
Like many close-in planets, KELT-9b is tidally locked to its star, meaning one side of the world is always facing its star, while the other side is permanently facing the chilling bla...