Scientists detect helium on planet outside our solar system for the first time

Andrew Griffin@_andrew_griffin
Wednesday 02 May 2018 17:11
This image of Jupiter was taken late last month as the Juno spacecraft performed a close flyby of the planet
This image of Jupiter was taken late last month as the Juno spacecraft performed a close flyby of the planet

Scientists have found an exoplanet with its own helium atmosphere for the first time.

The huge breakthrough marks a major step forwards in our understanding of the makeup of other planets. And it could eventually help us learn even more about them: understanding the atmosphere on planets far from our own, and eventually working out what life might be like there, or if they could host aliens.

The new finding comes after a team of researchers spotted evidence of the gas on a huge super-Neptune far away from our own solar system. The planet – named WASP-107b and found 200 light years away in the constellation Virgo – is a breakthrough that confirms many of scientists’ predictions about planets elsewhere in space.

They spotted such a strong signal coming from the planet that they think its atmosphere extends many tens of thousands of kilometres up into space.

Helium is the second most common element in the universe. Scientists long expected it would be found on planets elsewhere in the universe, as it is in gas giants Saturn and Jupiter in our own neighbourhood.

But the discovery is the first time it has actually been spotted elsewhere. And it was done using a technique that could help us understand much more about the planets that surround us.

With time, it could help us see the atmosphere of planets far deeper into the universe than those we have studied before. It uses infrared light, allowing it to spot planets with such tall atmospheres from a long distance.

“We hope to use this technique with the upcoming James Webb Space Telescope, for example, to learn what kind of planets have large envelopes of hydrogen and helium, and how long planets can hold on to their atmospheres,” said Jessica Spake, part of Exeter’s physics and astronomy department. “By measuring infrared light, we can see further out into space than if we were using ultraviolet light.”

WASP-107b is otherwise a strange planet. It has a very low density – it is a similar size to Jupiter, but has only 12 per cent of its mass – and is relatively cool for an exoplanet but still 500C hotter than Earth.

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