Helium Exoplanet Looks Like A Balloon, According To Scientists


Scientists identified a helium exoplanet, HAT-P-11b, located at about 124 light years from Earth, in the Cygnus constellation. This far-distant planet is, however, a special one as its atmosphere is made of helium and that makes this exoplanet look like a balloon, according to an international team of astronomers, led by researchers from the University of Geneva and involving Jessica Spake and Dr. David Sing from the University of Exeter.

HAT-P-11b is a Neptune-sized exoplanet with a very particular atmosphere which consists of helium. Thanks to the new data collected using the 4-meter telescope at Calar Alto, Spain, the astronomers managed to calculate the speed of helium atoms in the upper atmosphere of the exoplanet. Helium, therefore, shaped like a cloud surrounding the planet, is trying to escape the from HAT-P-11b like a helium balloon that rises to the skies when dropped.

The scientists hope that their groundbreaking findings might shed more light on the atmospheric phenomena that take place in the hottest planets of the Universe.

Helium Exoplanet Looks Like A Balloon

“This is a really exciting discovery, particularly as helium was only detected in exoplanet atmospheres for the first time earlier this year. The observations show helium being blasted away from the planet by radiation from its host star. Hopefully, we can use this new study to learn what types of planets have large envelopes of hydrogen and helium, and how long they can hold the gases in their atmospheres,” said Jessica Spake from the University of Exeter.

As this helium exoplanet is 20 times closer to its host star than our planet is from the Sun, “we suspected that this proximity with the star could impact the atmosphere of this exoplanet. The new observations are so precise that the exoplanet atmosphere is undoubtedly inflated by the stellar radiation and escapes to space,” explained Romain Allart from the University of Geneva.

“Helium is blown away from the day side of the planet to its night side at over 10,000 km an hour. Because it is such a light gas, it escapes easily from the attraction of the planet and forms an extended cloud all around it,” added the study’s leading author, Vincent Bourrier.


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