Astronomers discover ‘super-Jupiter’ giant exoplanet

A “super-Jupiter” giant exoplanet has been discovered orbiting a nearby star.

The observed exoplanet – a planet outside the solar system – is very bright and cold, with a mass more than six times that of Jupiter .

The detection is unusual in several ways, including that it shows the first exoplanet imaged with the James Webb Space Telescope (JWST) that had not already been imaged from the ground.

It is also much colder than the gas planets JWST has studied so far.

We were excited when we realised we had imaged this new planet

The recent observations lead the way to finding many more of these cold gas-giant planets, allowing astronomers to study a new class of exoplanets and compare them with the gas giants in our solar system.

Elisabeth Matthews, a researcher at the Max Planck Institute for Astronomy in Heidelberg , Germany , one of the authors of the paper, said: “We were excited when we realised we had imaged this new planet.

“To our surprise, the bright spot that appeared in our MIRI (Mid-Infrared Instrument) images did not match the position we were expecting for the planet.

“Previous studies had correctly identified a planet in this system but underestimated this super-Jupiter gas giant’s mass and orbital separation.”

The planet, named Eps Ind Ab, revolves around the main component of the nearby triple star system Epsilon Indi, or Eps Ind for short, which is only 12 light years from Earth.

It needs around 200 years to orbit its star.

Previous analyses of this star have indicated that it may host a giant planet, but there have been no direct observations.

The direct imaging of a planet by JWST offers new insights into the properties of this system, researchers say.

The scientists also attempted to understand the exoplanet’s atmosphere based on the available images of the planet.

The findings indicate there could be substantial amounts of heavy elements, particularly carbon, which builds molecules such as methane, carbon dioxide and carbon monoxide, commonly found in gas-giant planets.

Alternatively, it might indicate that the planet has a cloudy atmosphere, but more work is needed to reach a final conclusion.

Dr Matthews said: “In the long run, we hope to also observe other nearby planetary systems to hunt for cold gas giants that may have escaped detection.

“Such a survey would serve as the basis for a better understanding of how gas planets form and evolve.”

The findings are published in the Nature journal.