Astronomers Find Collapsed Exoplanets Sporting Comet-Like Tails

Using data from NASA’s transit exoplanetary survey satellite (TESS), MIT astronomers discovered a rocky exoplanet orbiting the bright K-Dwarf Star BD+05 4868A and observed variable transport depths, a feature of comet-like tails formed by the dusty effects expressing the distemination planet. This exoplanet-specific is the presence of a dust tail that is prominent in both subsequent and major directions, contributing to the extinction of starlight from the host star.

BD+05 4868A also known as TIC 466376085 or hip 107587, is about 140 light years away from the Pegasus constellation.

A new descattering named BD+05 4868AB approaches the star towards the sun at about 20 times the mercury, completing its orbit every 30.5 hours, but about the mass of mercury.

In close proximity to BD+05 4868A, the planet is roasted at about 1,600 degrees Celsius (3,000 degrees Fahrenheit) and may be covered in boiling magma in space.

Just as planets bubble around the stars, it strips off a huge amount of surface minerals and effectively evaporates.

MIT astronomer Marc Hon and colleagues discovered BD+05 4868AB using NASA’s Exoplanet Survey Satellite (TESS).

The signal that turned the astronomer over was a unique transport with a dip that all orbits were deeply fluctuating.

They confirmed that the signal is a tough orbital planet that has long been chasing comet-like fragments.

“The tail range is huge, extending up to 9 million km long, or about half the entire planet’s orbit,” Dr. Hong said.

“The planets collapse at a dramatic rate, and each time a star orbits the star, it appears to be throwing away the amount of material equivalent to Mount Everest.”

Researchers predict that the planet could completely collapse within about 1 to 2 million years.

Dr. Avi Shporer, an astronomer at MIT, said:

Of the almost 6,000 planets astronomers have discovered so far, scientists know only three other collapsed planets beyond our solar system.

Each of these crumbling worlds was discovered over a decade ago using data from NASA’s Kepler Space Telescope. All three planets were found with similar comet-like tails.

The BD+05 4868AB has the longest tail to date and has the deepest transits from four known collapsed planets.

“That means that its evaporation is the most devastating and disappears much faster than other planets,” Dr. Hong said.

Team’s result It will be published in Astrophysics Journal Letter.

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Markhon et al. 2025. A crumbling rocky planet with a prominent comet-like tail around a bright star. apjlin press; Arxiv: 2501.05431