A planet the size of Neptune, but located 33 times closer to the parent star than the Earth, loses its atmosphere, thus forming a thick “tail” similar to a comet.
Using the ultraviolet spectrograph of the Hubble telescope, scientists were able to see the planet Gliese 436b, located about 30 light years from Earth in the constellation Leo, during its passage in front of its parent star in December 2012, June 2013 and July 2014.
Observations of the last two passes were also carried out using the Chandra telescope, which is able to see in the X-ray spectrum.
Hydrogen in the atmosphere of the planet burns out due to the intense radiation of the parent star - a red dwarf, smaller than half of our sun. The planet rotates at a distance of only 2 million miles from its star. Earth, for example, is 93 million miles away from the Sun.
“The passage of ultraviolet particles steadily begins two hours before, and ends more than three hours after the optical transit, about 1 hour in length,” said Ehrenreich and his colleagues.
“This means that the hydrogen cloud is about 50 times larger than the parent star. “The tail” is formed due to the pressure of the ultraviolet light of the star on the leaking hydrogen, which causes it to spiral into a spiral, ”added Peter Wheatley, co-author of the work at the University of Warwick. Scientists estimate that 436b loses about a ton of hydrogen from its atmosphere every second. At first glance, this is a lot, however, in general, approximately 0, 1 percent of its total volume is lost every billion years.
“We believe that the planet may have lost up to ten percent of its atmosphere in the last 7 billion years,” says Ehrenreich.
The planet will not soon lose its entire atmosphere, but scientists assume that they have recorded the process of the emergence of the so-called “Hot Super-Earth”.
Super-Earths (or Super-Earths) are solid planets whose mass is several times the mass of the Earth, located close to their parent stars. According to new research, these worlds can originate from even more massive planets with a thick gas atmosphere, which gradually burned out over several eons.