NASA astronomers have recently discovered a Neptune-sized planet that’s leaving a trail of hydrogen gas behind it, making it look like a comet. It’s the first space object of its kind.
Data collected with the help of the Hubble Space Telescope has revealed that the hydrogen cloud released by the planet is able to exist the way it does due to the fact that the gas is not heated up and swept away quickly enough by the radiation pressure exhibited by the planet’s star which is fairly cool, and a red dwarf.
The planet itself is known as GJ 436b, and it’s thought to be roughly 50 times bigger than its parent star. It sits at 33 light years away from the Earth, in a constellation called Leo.
This type of world is somewhere between 10 and 20 times bigger than our planet, and stays as close to its star as Mercury does to our Sun, possibly even closer. It’s because of this that space scientists refer to it, as well as other similar planets, as Warm Neptune. GJ 436b in particular is 13 times closer to its star than Mercury is to our Sun, which also makes it 33 times closer to it than the Earth is to its star.
The cloud of hydrogen gas has been dubbed “The Behemoth”, has a circular appearance, a diameter that’s roughly 1.8 million miles (3 million km), and an unknown length as the astronomers have not been able to get a look at all of it. They do however offer a possible estimate of its length – 9.3 million miles (15 million km).
David Ehrenreich, lead author and astronomer at the University of Geneva’s observatory (Switzerland), gave a statement stressing just how astonished he was by the size of the gas cloud that’s escaping from the planet.
He went on to add the evaporation rate has not yet reached the point where it threatens the planet, and to inform how “we know that in the past, the star, which is a faint red dwarf, was more active. This means that the planet evaporated faster during its first billion years of existence because of the strong radiation from the young star”.
Ehrenreich and his team have estimated that the planet has most likely lost more than 10 percent (10%) of its atmosphere in the last several billion years and that it isn’t in any danger of evaporating its entire atmosphere.
The astronomers had to use the Hubble Space Telescope’s ultraviolet capability in order to find The Behemoth, as the cloud of hydrogen gas can not be seen in visible wavelengths.
Space scientists hope that continuing to observe the phenomenon will clue them in on how the same thing could happen to other planets with a hydrogen-enveloped atmospheres.
Image Source: phys.org
