Direct Imaging Technique
The discovery was made using the James Webb Space Telescope’s (JWST) Mid-InfraRed Instrument (MIRI). The planet orbits the K5V-type star Epsilon Indi A, located 12 light-years from Earth. The exoplanet has a temperature of about -1°C (30°F) and orbits its star at a distance 28 times greater than the Earth-Sun distance.
“Previous studies had correctly identified a planet in this system but underestimated its mass and orbital separation,” said Elisabeth Matthews from the Max Planck Institute for Astronomy and lead author of the research. With the help of the JWST, the team was able to accurately determine these properties.
Significance of the Discovery
“This discovery is a major milestone in exoplanet research and sets the stage for future discoveries,” said Manindra Agrawal, director of IIT-Kanpur. Dr. Prashant Pathak emphasized the importance of this discovery, highlighting its unusual atmospheric composition with a high metal content and a different carbon-to-oxygen ratio. He noted, “This opens up fascinating questions about its formation and evolution.”
Methodology and Future Research
The team decided to use a direct imaging approach due to the planet’s long orbital period of around 200 years. They used JWST’s MIRI camera equipped with a coronagraph to block starlight, enabling the detection of faint signals around bright objects. Dr. Pathak explained, “Previous attempts to study the planet were not successful as the planet’s orbital period is around 200 years and the data from short-term observations was not sufficient to accurately determine the planet’s properties.”
Thomas Henning, Emeritus Director at MPIA and co-PI of the MIRI instrument, stated, “Our next goal is to obtain spectra for a detailed fingerprint of the planet’s climatology and chemical composition. In the long run, we hope to also observe other nearby planetary systems to hunt for cold gas giants.”