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Scientists think they have identified such a dramatic lava world that it could boast a thin regional atmosphere of vaporized rock where it is closest to its star.
That exoplanet is called K2-141b and was originally discovered in 2017. The world is again about half the size of the Earth, but orbits so close to its star, which is a class smaller than ours, that it completes several rings each day of the Earth with the same surface permanently facing the star. Now, scientists predict that these factors mean that two thirds of K2-141b’s surface is permanently illuminated by the sun, so much so that not only part of the world is covered by a ocean of lava, but some of that rock could even evaporate into the atmosphere.
“All the rocky planets, including Earth, started out as molten worlds but then quickly cooled and solidified,” Nicolas Cowan, planetary scientist at McGill University in Canada and co-author of the new paper, he said in a statement. “The lava planets give us a rare glimpse at this stage of planetary evolution.”
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The scientists behind the new researchers wanted to understand what kind of atmosphere such a hot world might have and how Earth’s instruments would see it. The K2-141b was a tempting target because it was studied by both NASA’s K2 mission Kepler space telescope and the agency Spitzer space telescope. And the atmosphere is particularly intriguing because scientists believe NASA is imminent James Webb space telescope, scheduled for launch at the end of next year, will be able to analyze the components of distant planetary atmospheres.
The researchers started with what previous studies have determined so far on K2-141b – for example, that the planet’s density is about that of Earth, so the crust can be modeled as pure silica as a reasonably simplified representation. So, scientists figured out what the surface could look like. That work took into account complications such as the planet being so close to its star that more than half of the world’s surface could be illuminated by the sun, perhaps up to two-thirds, the researchers calculated.
Such constant light and heat mean the world likely sports an ocean of magma tens of miles or kilometers deep, according to the team’s calculations. Then, the researchers modeled what a atmosphere here it would seem based on three potential main ingredients, all common in the crusts of rocky planets.
All three cases can support an atmosphere, the scientists calculated, with wind speeds exceeding 1.1 miles (1.75 kilometers) per second, much faster than the speed of sound here on Earth.
At the edge of the atmosphere, where temperatures drop, the gaseous rock will cool enough to fall back to the surface as precipitation, the researchers calculated. If the atmosphere is dominated by silica or silicon monoxide, precipitation would fall mainly into the magma ocean, but if the atmosphere is predominantly sodium, the planet would look even stranger, with solid sodium oozing to the oceans like glaciers here on Earth, the researchers wrote.
But all this modeling wasn’t just to imagine what a truly bizarre world might look like; this is science, after all. The researchers wanted to compare their models with the current and anticipated observing capabilities of huge space telescopes. Here, the scientists are optimistic: they call K2-141b “a particularly good target for atmospheric observations”.
And the researchers also have a way to pass their time before the launch of the James Webb Space Telescope, the scientists said in the statement: They have acquired observations from the Spitzer Space Telescope that should help define temperatures on the day and night sides of the planet. , clarifying how models can correspond to reality.
The research is described in a document published on November 3 in the journal Monthly Notices of the Royal Astronomical Society.
Email Meghan Bartels at [email protected] or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.
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