Scientists have spied a new, possible “game-changer” of a planet in the depths of space.
Known as Gliese 436b, or GJ 436b, the exoplanet is the size of Neptune and is trailed by a gas stream similar to that of a comet, according to a journal article published in Nature this week. Scientists working at NASA’s Hubble Space Telescope and the Chandra X-ray Observatory discovered it 33 light years away from Earth orbiting a red dwarf star and it is the first exoplanet of its kind ever seen, NBC News reported.
A University of Warwick press release showed artist Mark Garlick’s depiction of the discovery. In the release, Peter Wheatley, one of the Nature article’s co-authors, explained that ultraviolet light from the nearby star causes the planet’s hydrogen to spiral outwards, forming the comet-like tail.
The rare combination of this relatively small exoplanet being engulfed in this massive hydrogen cloud makes Gliese 436b unique.
“This cloud of hydrogen is very spectacular!” wrote David Ehrenreich, lead author of the study, in a release from the European Space Agency. “Although the evaporation rate doesn’t threaten the planet right now, we know that the star, a faint red dwarf, was more active in the past. This means that the planet’s atmosphere evaporated faster during its first billion years of existence. Overall, we estimate that it may have lost up to 10 percent of its atmosphere.”
The researchers believe the gaseous cloud, or tail, trailing the exoplanet is able to remain largely intact because the planet’s red dwarf star is relatively cool, not emitting enough radiation to sweep the gas away.
The exoplanet is burning off 1,000 metric tons of hydrogen a second, but that only means it’s losing 0.1 percent of its total mass every billion years, Wheatley said. The researchers believe exoplanets similar to this are likely burning off gas at a much faster rate.
The discovery could explain “hot-super Earths,” planets that orbit closer to their stars but are usually more massive than Earth, the ESA release said.
“Finding the cloud around Gliese 436b could be a game-changer for characterizing atmospheres of the whole population of Neptunes and Super-Earths in ultraviolet observations,” said Vincent Bourrier, another co-author.
Gliese 436b is about 23 times the size of Earth, comparable to the size of Neptune, and is actually referred to as a “warm Neptune” because of its relative proximity to its star, Gliese 436 — in other words, this planet is closer to its star than our Neptune is to the Sun.
“You wouldn’t be able to see it at visible wavelengths,” said Ehrenreich, noting how Earth’s atmosphere prevents us from seeing most ultraviolet light. “But when you turn the ultraviolet eye of the Hubble onto the system, it’s really quite a transformation — the planet turns into a monstrous thing.”