New-found exoplanet is evaporating away

Posted by Emma Woollacott

MIT and NASA scientists believe they've found a planet, 1,500 light years away, that appears to be disintegrating from the heat of its parent star.

The planet circles its parent star every 15 hours — one of the shortest planetary orbits ever observed, implying it orbits very close to its star.

This would heat it to about 3,600 degrees Fahrenheit, and cause rocky material at the surface of the planet to melt and evaporate, forming a wind that carries both gas and dust into space.

Dense clouds of the dust trail the planet as it speeds around its star - explaining why the star dims every 15 hours.

"I’m not sure how we came to this epiphany," says MIT professor emeritus of physics Saul Rappaport. "But it had to be something that was fundamentally changing. It was not a solid body, but rather, dust coming off the planet."

The team's calculations indicate that it'll disappear completely within 100 million years.

The team investigated various ways in which dust could be created and blown off a planet. It would have to have a low gravitational field, much like that of Mercury, and be extremely hot — on the order of 3,600° F.

Rappaport says there are two possible explanations for how the planetary dust might form: It might erupt as ash from surface volcanoes, or it could form from metals that are vaporized by high temperatures and then condense into dust.

"This might be another way in which planets are eventually doomed," says Dan Fabrycky, a member of the Kepler Observatory science team.

"A lot of research has come to the conclusion that planets are not eternal objects, they can die extraordinary deaths, and this might be a case where the planet might evaporate entirely in the future."