Steamy atmosphere detected around ‘water world’ exoplanet

7 Apr 2017

Illustration of alien atmosphere. Image: Igor Zh./Shutterstock

Astronomers observing a distant Earth-like exoplanet have discovered a steamy atmosphere, which suggests it could be a fascinating ‘water world’.

More and more frequently, news is emerging on newfound exoplanets scattered throughout the universe, which have been spotted to have Earth-like qualities.

As recently as February, Belgian astronomer Michael Gillon announced the discovery of a new star system with seven Earth-like planets called TRAPPIST-1, which offered hope in the search for the irrefutable existence of alien life.

A team from Keele University in the UK has revealed yet another major exoplanet discovery, this time with confirmation of an atmosphere – the first confirmed sighting of one outside our own planet.

The planet in question is called GJ 1132b, located 39 light years away from Earth but much bigger, and sweltering.

“We simulated a range of possible atmospheres for this planet, finding that those rich in water and/or methane would explain the observations of GJ 1132b,” explained Dr John Southworth, who led the research.

“The planet is significantly hotter and a bit larger than Earth (1.4 times), so one possibility is that it is a ‘water world’ with an atmosphere of hot steam.”

Using the European Southern Observatory’s (ESO) powerful telescopes, GJ 1132b passes directly between Earth and its host star every 1.6 days, blocking a small fraction of the star’s light.


Artist’s concept image of GJ 1132b. Image: MPIA

Hopes of finding life increases

The planet’s size seemed to differ over several wavelength bands, and Southworth and his team were able to determine that this was down to the existence of an atmosphere.

As GJ 1132b orbits a very low-mass star – a very common sight in the universe – the discovery of an atmosphere was surprising as typically, these stars emit high levels of damaging x-rays and ultraviolet light.

This suggests that atmospheres in the wider universe are stronger than we once thought, possibly meaning suitable conditions for life.

The discovery makes GJ 1132b one of the highest-priority targets for further study by the current top facilities, such as the Hubble Space Telescope and ESO’s Very Large Telescope, as well as the James Webb Space Telescope, which is slated for launch in 2018.

The team’s research has now been published in The Astronomical Journal.

Colm Gorey was a senior journalist with Silicon Republic