‘Rocky’ climate can change the surface and atmosphere over time exoplanet K 2-141 b.

Among the most intense planets found beyond the edges of our solar system are the lava planets: intensely hot worlds very close to their host star, and some areas are oceans of molten lava. According to scientists at McGill University, York University and the Indian Institute of Science Education, at least one exoplanet’s atmosphere and even the weather cycle are unfamiliar, with rocks evaporating and precipitating, with supersonic winds of more than 5,000 kilometers per hour and depths of up to 100 kilometers per hour.

In a study published in Monthly Notices of the Royal Astronomical Society, Scientists using computer simulations K2-141b, Earth-sized exoplanet, surface, ocean, and atmosphere all made of the same ingredients: rocks. The harsh weather predicted by their analysis will permanently change the surface and atmosphere of K2-141b over time.

The first predictions of the weather at K2-141b could be made hundreds of light-years away using next-generation telescopes. James Webb Space TelescopeJiang Guin, a leading author and PhD student at York University, says the study was overseen by McGill University professor Nicholas Cowan.

Two-thirds of the exoplanet faces endless daylight

When analyzing the light pattern of the exoplanet, the team found that two-thirds of K2-141b faces constant daylight – brighter than the luminous hemisphere we used on Earth. K2-141b belongs to a subgroup of rocky planets that are very close to their star. This proximity locks the exoplanet by gravity, meaning that the same side is always facing the star.

Feels below -200C at night. At daytime temperatures of 3000 C, the exoplanet is capable of not only melting rocks but also evaporating them, ultimately creating a thin atmosphere in some areas. “Our discovery means that the atmosphere extends beyond the shores of the Magma Ocean, making it easier for space telescopes to detect,” said Nicholas Cowan, professor of Earth & Planetary Sciences at McGill University.

Like the earth’s water cycle, only with rocks

It is noteworthy that the rock vapor atmosphere created by extreme heat is subject to moisture. Sodium, silicon monoxide, and silicon dioxide in K2-141b also occur as water evaporates, rises, condenses, and falls back into the atmosphere as the Earth’s water cycle. On Earth, rain flows back into the ocean, where it evaporates again and the water cycle repeats itself. In K2-141b, supersonic winds and rocks “rain” back into a magma ocean at night, forming mineral vapor formed by evaporated rock. The resulting current flows back to the hot day of the exoplanet, where the rock evaporates again.

However, scientists say that the cycle of K2-141b is not as stable as on Earth. The return of the magma ocean to the daytime is slow, and as a result they predict that the mineral composition will change over time – eventually changing the surface and atmosphere of K2-141b.

“All rocky planets, including Earth, began as molten worlds but quickly cooled and solidified. At this stage of planetary evolution, lava planets give us a rare view, ”says Cowan, a professor in the Department of Earth and Planetary Sciences.

The next step is to test whether these predictions are correct, scientists say. The team now has data from the Spitzer Space Telescope that should give a first-hand look at the day and night temperatures on the exoplanet. With the launch of the James Webb Space Telescope in 2021, they will also be able to test whether the atmosphere is working as predicted.

Reference: “Lava Planet Atmospheric Modeling: K2-141b: Indications for Low and High Resolution Spectroscopy” t. Giang Guin, Nicholas Cowan, Agniba Banerjee, John Moores, November 3, 2020, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093 / mnras / staa2487