Astronomers have found the first evidence of tectonic activity on an exoplanet


You may not be very familiar with the planet LHS 3844b, but it now has its own particular distinction: It is the first planet outside our Solar System where astronomers think they might have evidence of tectonic activity.

That evidence is a set of advanced simulations based on observations of the rocky planet, which is slightly larger than Earth. Importantly, for this particular investigation, the exoplanet does not appear to have an atmosphere.

That leaves half of LHS 3844b permanently exposed to your sun and could mean temperatures as high as about 800 degrees Celsius (1,472 degrees Fahrenheit) on the ‘daytime’ side, and about minus 250 degrees Celsius (minus 418 degrees Fahrenheit) at ‘night. time side.

“We think that this strong temperature contrast could affect the flow of material inside the planet,” says astronomer Tobias Meier, of the University of Bern in Switzerland.

Based on observations of the phase curve of the planet’s brightness and possible temperatures, and computer models that simulate various possible tectonic materials and heat sources, Meier and his colleagues believe that an underground material flow is occurring on a hemispheric scale.

Most of the simulations the researchers conducted showed only upward flow on one side of the planet and only downward flow on the other, but in some scenarios that was reversed – a surprising finding that does not match tectonic motion on the earth.

“Based on what we are used to from Earth, you would expect material on the warm side of the day to be lighter and therefore flow upward and vice versa,” says geophysicist Dan Bower of the University of Bern.

The underlying reason is the changing temperature of the mantle material as it moves, with colder rocks hardening and becoming less mobile, and warmer rocks becoming much more liquid as they heat up. Scientists say the changing surface and material could lead to some pretty incredible tectonic activity.

“On whatever side of the planet the material is flowing upward, you would expect a lot of volcanism on that particular side,” says Bower.

As a result, scientists suggest that LHS 3844b could have an entire hemisphere covered in volcanoes, while the other side barely shows volcanic activity, all due to the intense temperature contrast around the planet.

The type of outcrop these volcanoes would cause matches what we see on Earth, but only in specific places, like Hawaii and Iceland. More generally, the tectonic motion suggested by these models is unlike anything in our Solar System.

As more powerful space telescopes come online and our understanding of exoplanets improves, further observations and research should help confirm what is happening on the surface of LHS 3844b, and whether it is actually half covered by volcanoes.

“Our simulations show how such patterns can manifest, but more detailed observations would be required to verify,” Meier says.

“For example, with a higher resolution map of surface temperature that could point to increased outgassing by volcanism or volcanic gas detection. This is something that we hope future research will help us understand.”

The research has been published in the Astrophysical journal letters.

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