This Neptune-Sized Exoplanet Is Being Melted Away By Its Star
|futurism.com 14 Dec 2018 at 13:17|
A newly discovered gas planet, orbiting a distant star, is approximately the size of NeptuneÂ â€” but itâ€™s so close to the red dwarf it orbits that itâ€™s literally boiling away.
â€śThis is the smoking gun that planets can lose a significant fraction of their entire mass,â€ť Johns Hopkins planetary scientist David Sing, who helped find the exoplanet, said in a news release . He added that itâ€™s â€ślosing more of its mass than any other planet we seen so far; in only a few billion years from now, half of the planet may be gone.â€ť
The planet, which is called GJ 3470b and described in a new paper Â in the journalÂ Astronomy & Astrophysics, is whatâ€™s known as a â€śhot Neptune.â€ť That means that itâ€™s a gas giant, like our own solar systemâ€™s Neptune or Jupiter, but itâ€™s far closer to its host star than either of those planets.
GJ 3470b is so close to its star, in fact, that itâ€™s boiling away into space. To make matters worse, itâ€™s not a very heavy planet, meaning that its gravitational pull on its own atmosphere is comparatively weak.
The rapidly vanishing GJ 3470b could provide an important clue about the nature of gas planets outside our solar system. Though the Kepler mission has found many smaller â€śmini-Neptunesâ€ť sprinkled throughout the galaxy, hot Neptunes are rare. The new theory: weâ€™re not finding as many hot Neptunes because, like GJ 3470b, they tend to boil away into mini-Neptunes.
â€śItâ€™s one of the most extreme examples of a planet undergoing a major mass-loss over its lifetime,â€ť University of Geneva astronomer Vincent Bourrier, another researcher on the hot Neptune project, said in the same news release. â€śThis sizable mass loss has major consequences for its evolution, and it impacts our understanding of the origin and fate of the population of exoplanets close to their stars.â€ť