New theory says evaporating exomoon explains Tabby’s Star

Astronomers have proposed a new theory for the random and inexplicable light variations that Tabby’s Star undergoes, a melting and evaporating exomoon.

The Columbia team suggests that Tabby’s Star abducted an exomoon from a now long-gone, nearby planet and pulled it into orbit around itself, where it has been getting torn apart by stronger stellar radiation than existed in its former orbit. Chunks of the exomoon’s dusty outer layers of ice, gas, and carbonaceous rock have been able to withstand the radiation blow-out pressure that ejects smaller-grain dust clouds, and the volatile, large-grain material has inherited the exomoon’s new orbit around Tabby’s Star, where it forms a disk that persistently blocks the star’s light. The opaqueness of the disk can change slowly, as smaller-grain clouds pass through and larger particles stuck in orbit move from the disk toward Tabby’s Star, eventually getting so hot that they melt and fall onto the star’s surface.

Ultimately, after millions of years, the exomoon orbiting Tabby’s Star will completely evaporate, the researchers suggest.

The article does not explain why the theory requires this exoplanet to have once been a moon to another exoplanet, now gone. It seems to me that this is adding unnecessary complexity to the solution, but I have not read the paper itself, so their might be reasons.

Have astronomers using Kepler discovered the first exomoon?

The uncertainty of science: Using data from Kepler astronomers think they have spotted the first exomoon, orbiting a star 4,000 light years away.

They think it might be the size of Neptune, and orbits a planet about ten times more massive than Jupiter.

All this is unconfirmed, however, especially because their conclusions are based on data from only three transits. They plan to use the Hubble Space Telescope to do more observations and hopefully confirm the discovery.