James Webb spots 'super Jupiter' and it is one of the coldest exoplanets observed to date

James Webb Space Telescope, which is the largest and most powerful telescope ever launched into space, spotted a "super Jupiter" around a neighbouring star — and it has a super orbit. The exoplanet is the 12th closest exoplanet to Earth known to date. It is also the closest planet biggerthan Jupiter.

The National Aeronautics and Space Administration (NASA) said that the planet, Epsilon Indi Ab, is one of the coldest exoplanets observed to date.

The planet is roughly the same diameter as Jupiter but with six times the mass. The big difference is that it takes this planet more than a century, possibly as long as 250 years, to go around its star. Its atmosphere is also rich in hydrogen similar to that of Jupiter.

An international team of astronomers observed Epsilon Indi Ab using the coronagraph on Webb's MIRI (Mid-Infrared Instrument). The feat is extraordinary as the exoplanet has been directly imaged and only a few tens of exoplanets have been directly imaged previously by space- and ground-based observatories.

The exoplanets that have been previously photographed are often the hottest and youngest, still emitting a significant amount of energy from their initial formation. Planets get fainter and more difficult to image as they cool and contract during their lifetime.

The research article, titled "A temperate super-Jupiter imaged with JWST in the mid-infrared" was published in the journal Nature on Wednesday (Jul 24).

As quoted by NASA, Elisabeth Matthews, a researcher at the Max Planck Institute for Astronomy in Heidelberg, Germany, said: "This discovery is exciting because the planet is quite similar to Jupiter — it is a little warmer and is more massive, but is more similar to Jupiter than any other planet that has been imaged so far."

Matthews further explained, "Cold planets are very faint, and most of their emission is in the mid-infrared. Webb is ideally suited to conduct mid-infrared imaging, which is extremely hard to do from the ground. We also needed good spatial resolution to separate the planet and the star in our images, and the large Webb mirror is extremely helpful in this aspect."

Caroline Morley of the University of Texas at Austin, who is a team member, said, "Our prior observations of this system have been more indirect measurements of the star, which actually allowed us to see ahead of time that there was likely a giant planet in this system tugging on the star. That's why our team chose this system to observe first with Webb."

(With inputs from agencies)