“Escaping gas has been seen in the past for larger gas giant exoplanets, so it was a surprise that looking at a much smaller planet resulted in such a big and stunning comet-like display,” said study co-author David Sing, professor at University of Exeter in Britain.
With a mass approximately 23 times that of our Earth located 33 light years away, the exoplanet GJ436b rotates around its star in only three days and has an atmosphere which leaves behind a gigantic trail of hydrogen.
The scientists were able to see this hydrogen cloud’s shadow when it passes in front of the star.
GJ436b resides very close to its star less than two million miles and whips around it in just 2.6 Earth days. In comparison, the Earth is 93 million miles from our sun and orbits it every 365.24 days.
“This cloud of hydrogen is very spectacular!” said David Ehrenreich of the Observatory of the University of Geneva in Switzerland, lead author of the study. “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.”