Of all of the varieties of exoplanets researchers have discovered in recent years with ever more powerful telescope technology, the so-called “hot Jupiters” could be probably the most fascinating. They’re not the sort of planets we’d ever expect to find life on the planet. However, they’re so unlike anything we see in our solar system you can’t help but wonder what they might be similar.
Hot Jupiter planets are, as their title suggests, gas giants like our own Jupiter, however much, a lot warmer. The planets orbit much closer to their star than Jupiter does, and that generates temperatures to spike. Now, new research using data from each the Spitzer telescope and the venerable Hubble reveals something very fascinating concerning the strange, swirling masses of hot gas.
Because hot Jupiters orbit their stars so closely, they’re often tidally locked to their host star, which means that one side of the planet is at all times facing the sun while the opposite side is always dark. However, as a result of the temperatures of the sunlit side of the gaseous worlds can vary by nicely over a thousand degrees, you may think the dark sides of various hot Jupiters wouldn’t have a lot in familiar with one another.
The research suggests that this isn’t the case and that the dark side temperatures of hot Jupiters are usually quite similar. Of the 12 hot Jupiters examined within the study, the dark sides of the planets were all around 800°C or 1472°F.
“Atmospheric circulation models predicted that nightside temperatures should vary much more than they do,” first author Dylan Keating said in a statement. “That is unusual as a result of the planets we studied all receive different amounts of irradiation from their host stars, and the dayside temperatures among them varies by nearly 1700°C.”
For the temperatures of the dark sides of hot Jupiters to stay so consistent, the researchers believe there must be some insulating features like mineral-rich clouds keeping them at a constant temperature.