IIT Kanpur prof finds 'Super Jupiter' exoplanet using James Webb telescope

The newly discovered planet, more massive than Jupiter, orbits a K-type star Epsilon Indi A (Eps Ind A), which shares similarities in age with our Sun but is slightly cooler

In a significant breakthrough, Prashant Pathak from the Indian Institute of Technology (IIT) Kanpur, alongside a team of global astronomers, discovered a massive planet comparable to the Sun, in terms of size.

According to a press statement by the institute, Pathak from the Department of Space, Planetary & Astronomical Sciences, and Engineering (SPASE) at IIT Kanpur collaborates with an international astronomy team to identify the planet using direct imaging techniques. The team utilised the Mid-InfraRed Instrument (MIRI) of the James Webb Space Telescope (JWST) to make the discovery.
 

What is the Super Jupiter planet?

The newly discovered planet, which is more massive than Jupiter, orbits the K-type star Epsilon Indi A (Eps Ind A), which shares similarities in age with our Sun but is slightly cooler, US space agency Nasa said. The team utilised the coronagraph on Webb’s MIRI to observe Epsilon Indi Ab. Only a limited number of exoplanets have previously been directly imaged by both space and ground-based observatories.

Epsilon Indi Ab stands out as one of the coldest exoplanets ever detected, with an estimated temperature of 35 degrees Fahrenheit (2 degrees Celsius). This makes it colder than any other imaged planet beyond our solar system, except for one free-floating brown dwarf. 

Remarkably, this planet is only about 100 degrees Celsius (180 degrees Fahrenheit) warmer than the gas giants in our solar system, providing a unique opportunity for astronomers to study the atmospheric composition of true solar system analogs.

“This discovery is thrilling because the planet closely resembles Jupiter — it is somewhat warmer and more massive, but it is more similar to Jupiter than any other imaged planet so far,” noted lead author of the research Elisabeth Matthews from the Max Planck Institute for Astronomy in Germany.

Significance of the discovery of the exoplanet

Epsilon Indi Ab is currently the twelfth closest exoplanet to Earth and the nearest planet more massive than Jupiter. The scientific team chose to study Eps Ind A due to its indications of a potential planetary body from radial velocity measurements, which detect the host star’s back-and-forth movements along our line of sight.

“While we anticipated imaging a planet in this system based on radial velocity signs, the planet we discovered was unexpected,” stated Matthews. “It is about twice as massive, slightly further from its star, and has an unexpected orbit. The reasons for these discrepancies remain uncertain. Additionally, the planet’s atmosphere seems to differ from model predictions. So far, we have only a few photometric measurements of the atmosphere, making it challenging to draw definitive conclusions. However, the planet is dimmer than expected at shorter wavelengths.”

Planet may contain methane, CO2  

The team expects that the planet’s atmosphere might contain significant amounts of methane, carbon monoxide, and carbon dioxide, which absorb shorter wavelengths of light. This could also indicate a very cloudy atmosphere.

The direct imaging of exoplanets is invaluable for characterisation, allowing scientists to collect light directly from the planet and compare its brightness across different wavelengths. 

Although the team has only detected Epsilon Indi Ab at a few wavelengths so far, they aim to revisit the planet with Webb for more detailed photometric and spectroscopic observations. Additionally, they hope to identify other similar planets with Webb to uncover potential atmospheric trends and understand how these objects form, Nasa said.