Astronomers have discovered a planet so extreme that it that makes our “twisted” sister planet, Venus –with its 900 degrees Fahrenheit heat, corrosive sulfuric clouds, and a surface atmosphere 90 times denser than Earth’s that has crushed nine Soviet probes –seem like a Disney World theme park.
A Strange, Terrifying Planet
Scientists from McGill University, York University, and the Indian Institute of Science Education, have announced the discovery of an strange Earth-sized exoplanet, K2-141b, that features “the evaporation and precipitation of rocks, supersonic winds that rage over 5000 km/hr, a molten magma ocean 100 kilometers deep, and endless daylight for two-thirds of its surface.”
First Weather Predictions –An Atmosphere of Rocks
“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,” says lead author Giang Nguyen at York University who worked with the team using computer simulations to predict the conditions on K2-141b with a surface, ocean, and atmosphere all made up of the same ingredients: rocks. The extreme weather forecasted by their analysis could permanently change the surface and atmosphere of K2-141b over time.
Perpetual Daylight, 3000 C, Vaporized Rocks
McGill University reports that the team discovered that about two-thirds of K2-141b faces perpetual daylight – rather than the illuminated hemisphere we are used to on Earth. K2-141b belongs to a subset of rocky planets that orbit very close to their star. This proximity keeps the exoplanet gravitationally locked.
The night side experiences frigid temperatures of below -200 C. The day side of the exoplanet, at an estimated 3000 C, is hot enough to not only melt rocks but vaporize them as well, ultimately creating a thin atmosphere in some areas.
“Our finding likely means that the atmosphere extends a little beyond the shore of the magma ocean, making it easier to spot with space telescopes,” says Nicolas Cowan, a professor in the Department of Earth & Planetary Sciences at McGill University.
The rock vapor atmosphere created by the extreme heat undergoes precipitation, just like the water cycle on Earth, reports McGill, “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 vapor 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.”
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.
Rare Glimpse of a Molten World
“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 Giang Nguyen’s Ph.d supervisor, Nicolas Cowan.
Next Steps–Enter Spitzer & James Webb Space Telescope
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.
Source: “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.
The Daily Galaxy, Jake Burba, via McGill University
Image credit: K2-141b: Julie Roussy, McGill Graphic Design