Researchers from McGill University, York University, and the Indian Institute of Science Education have reported the detection of a weird Earth-sized exoplanet, K2-141b, which contains “the evaporation and precipitation of rocks, supersonic winds that rage over 5000 km / h, a molten magma ocean 100 kilometres deep, and endless sunshine over two-thirds of its atmosphere.”
Lead author of research published in Monthly Notices of the Royal Astronomical Society, Giang Nguyen at York University, said: “The study is the first to make predictions about weather conditions on K2-141b that can be detected from hundreds of light years away with next-generation telescopes such as the James Webb Space Telescope,”
McGill University claims that the team has found that about two-thirds of K2-141b experiences eternal sunshine – rather than the illuminated hemisphere we are accustomed to on Earth. K2-141b belongs to a class of rocky planets which orbit very close to their stars. This proximity holds the exoplanet gravitationally locked.
Like Earth’s water cycle, only with rocks
Remarkably, the rock vapour atmosphere created by the extreme heat undergoes precipitation. Just like the water cycle on Earth, where water evaporates, rises into the atmosphere, condenses, and falls back as rain, so too does the sodium, silicon monoxide, and silicon dioxide on K2-141b. On Earth, rain flows back into the oceans, where it will once more evaporate and the water cycle is repeated. On K2-141b, the mineral vapour formed by evaporated rock is swept to the frigid night side by supersonic winds and rocks “rain” back down into a magma ocean. The resulting currents flow back to the hot day side of the exoplanet, where rock evaporates once more.
Still, the cycle on K2-141b is not as stable as the one on Earth, say the scientists. The return flow of the magma ocean to the day side is slow, and as a result they predict that the mineral composition will change over time – eventually changing the very surface and atmosphere of K2-141b.
“All rocky planets, including Earth, started off as molten worlds but then rapidly cooled and solidified. Lava planets give us a rare glimpse at this stage of planetary evolution,” says Professor Cowan of the Department of Earth and Planetary Sciences.
The next step will be to test if these predictions are correct, say the scientists. The team now has data from the Spitzer Space Telescope that should give them a first glimpse at the day-side and night-side temperatures of the exoplanet. With the James Webb Space Telescope launching in 2021, they will also be able to verify whether the atmosphere behaves as predicted.
About the study
"Modelling the atmosphere of lava planet K2-141b: implications for low and high resolution spectroscopy" by T. Giang Nguyen, Nicolas Cowan, Agnibha Banerjee and John Moores is published in Monthly Notices of the Royal Astronomical Society.
You can read the research paper here and official news from McGill University here.
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