Among the most extreme exoplanets discovered to date are worlds orbiting so close to their star that some regions are just oceans of molten lava. Astronomers recently analyzed the weather cycle of one of these planets.
Our planet might seem inhospitable in some places, at some times, but bless heaven you don't live on exoplanet K2-141b, 202 light years away . This massive rocky world, discovered in 2018 by Kepler, evolves very close to its star (an orange dwarf), completing an orbit in 6.7 hours only . This proximity then creates unique environmental conditions, which researchers have recently tried to simulate. And the least we can say is that K2-141 b looks nothing like what we have already seen in the solar system.
“The study is the first to make predictions about the weather conditions observed on K2-141b. Conditions that could be detected hundreds of light-years away by next-generation telescopes, such as the James Webb Telescope” , says Giang Nguyen of York University.
Because of its proximity to its star, the planet is said to be "locked". In other words, like the Moon with the Earth, it presents him with only one face. On the "day" side, temperatures are naturally very high, estimated at about 2730°C at the surface . That said, astronomers believe that K2-141b is largely covered by an ocean of magma that could easily be one hundred kilometers deep .
Based on proposed simulations, reported in the Monthly Notices of the Royal Astronomical Society , this bubbling ocean would follow a cycle similar to that of water on Earth . On the surface, rocks and minerals (sodium, silicon monoxide and silicon dioxide) evaporate, creating a thin atmosphere hovering above the planet. It could extend beyond the "day" side, boosted by supersonic winds blowing at around 5,000 kilometers per hour!
These winds would then bring this warm, rocky "air" to the approaches to the night side, where temperatures are much cooler (about -200°C). In these conditions,the rocks cool down and rain down on the surface, before being re-routed towards the ocean of magma.
This new study is important, as all the rocky planets, including Earth, started out that way. Our planet, about 4.5 billion years ago, was indeed only a world in fusion. All cool and then solidify rapidly. Also, lava planets, like K2-141b, give us rare insight into this stage of planetary evolution.
