Massachusetts Institute of Technology astronomers have discovered a planet roughly 140 light-years from Earth — but it’s quickly disintegrating.
The planet, which scientists have tagged as BD+05 4868 Ab, is located so close to the sun that it completes a full orbit every 30.5 hours, according to MIT News. As a result, it’s likely covered in magma, causing the planet to evaporate and shed the equivalent of one Mount Everest’s worth of surface materials during every orbit.
The astronomers estimate the planet may disintegrate fully within the next 1 to 2 million years.
Debris trails behind the planet in a comet-like fashion, which is how the astronomers first detected it with NASA’s Transiting Exoplanet Survey Satellite (TESS).
“We got lucky with catching it exactly when it’s really going away,” Avi Shporer, a collaborator on the discovery who is also at the TESS Science Office, told MIT News. “It’s like, on its last breath.”
The recent discovery is a rare find for astronomers. Among the 6,000 planets identified thus far, only three of them are disintegrating planets beyond our solar system — and BD+05 4868 Ab has a longer tail than all of them.
Marc Hon, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research in Cambridge, describes the planet’s tail as “gargantuan” and told MIT News it’s up to 9 million kilometers long. That’s about half of the planet’s orbit around the sun.
However, the astronomers estimate the planet has a low mass and low gravity, which is contributing to its quick disintegration.
“This is a very tiny object, with very weak gravity, so it easily loses a lot of mass, which then further weakens its gravity, so it loses even more mass,” Shporer told MIT News. “It’s a runaway process, and it’s only getting worse and worse for the planet.”
Hon and graduate student Nicholas Tusay from Penn State University will continue to study BD+05 4868 Ab this summer with NASA’s James Webb Space Telescope, according to MIT News. The special telescope can help astronomers learn about the mineral makeup of the planet’s dust trail by identifying which colors of infrared light it absorbs.
“This will be a unique opportunity to directly measure the interior composition of a rocky planet, which may tell us a lot about the diversity and potential habitability of terrestrial planets outside our solar system,” Hon said.
