A team of scientists has assembled a new model describing the climate characteristics of the hellishly hot exoplanet, K2-141b, and it sounds like a real estate brochure for Mustafar. The model predicts that K2-141b, an Earth-size planet outside of our solar system, is so hot that its atmosphere, surface, and ocean are all made up of rocks. The model also predicts that K2-141b has supersonic winds to whip said rocks around the planet.
In terms of the weather predictions, K2-141b seems very much “bad place” indeed. Two-thirds of the planet endures perpetual daylight due to its being tidally locked. (I.e. K2-141b rotates at such a speed so that its same side always faces its host star.) Thanks to this intense light, and the short distance between K2-141b and its star, the planet’s “day side” is a constant 5,432 °F. For reference, a commercial pizza oven blasts pies at a relatively paltry 800 °F.
This extraordinary heat means K2-141b’s surface is likely mostly covered with molten lava—it’s literally classified as a “lava planet”—which means it’s hot enough to not just melt rock, but vaporize it. And it’s this vaporization of rock that gives K2-141b its “water cycle,” which does work much like Earth’s. (An illustration of a lava planet is immediately above for those wondering what one looks like.)
In essence, K2-141b’s rock cycle occurs when the planet’s rock-vapor atmosphere undergoes precipitation. Just as with Earth’s water cycle, where water evaporates, condenses, and falls as rain, so too does rock on K2-141b.
More specifically, the planet’s heat evaporates rock into mineral vapor; 3,100-mile-per-hour winds, in turn, carry the vapor to the “nighttime” side of the exoplanet, where it’s freezing. (It’s -328 °F on the planet’s dark side.) There, the mineral vapor condenses, and “rains” back down on one of the planet’s magma oceans. The minerals subsequently travel back to the planet’s day side, where the process begins anew.
Research from #McGill, @yorkuniversity and @iiserkol scientists finds that lava exoplanets can feature the evaporation and precipitation of rocks 🌧, supersonic winds 💨 that rage over 5000 km/hr, and a magma ocean 100 km deep 🔥🔥. https://t.co/bGd0I5uFRt pic.twitter.com/7NEP4jNFAG— McGill University (@mcgillu) November 4, 2020
“All rocky planets, including Earth, started off as molten worlds but then rapidly cooled and solidified,” Nicolas Cowan said in a McGill University press release. Cowan, a professor of planetary sciences at the University who supervised the model’s development, added that “Lava planets [like K2-141b] give us a rare glimpse at this stage of planetary evolution.” They also, after the year 2020 is said and done, may offer relatively appealing options for a new home planet.