JWST reveals clues to the atmosphere of Jupiter-analog exoplanet epsilon Eridani b

Star system: Epsilon Eridani | Distance from the Sun: 10.5 light years

Scientists conducted the most sensitive direct imaging search for the nearby Jupiter-analog exoplanet epsilon Eridani b using the JWST/NIRCam coronagraph between 4 and 5 micrometers. Despite achieving a record-breaking contrast sensitivity at the planet’s expected separation, the planet itself was not directly imaged. The study updated the age of the host star epsilon Eridani to 1.1 billion years, which affects the estimated temperature of the planet, now thought to be between 150 and 200 kelvin.
By applying advanced atmospheric models, the researchers found that the non-detection of epsilon Eridani b in the F444W filter can be explained if the planet’s atmosphere is enriched with metals or contains water ice clouds. These atmospheric properties would make epsilon Eridani b’s atmosphere similar to that of Jupiter in our Solar System. If the planet’s mass is lower than previously thought, a cloud-free, solar metallicity atmosphere could also explain the observations.
The team also placed limits on the size of a possible ring system around the planet and discussed future opportunities to directly image epsilon Eridani b with upcoming instruments and observatories.
Key findings
JWST/NIRCam achieved the deepest contrast sensitivity for direct imaging of epsilon Eridani b, but the planet was not detected.
The planet’s atmosphere may be metal-rich and/or contain water ice clouds, resembling Jupiter’s atmosphere.
Future observations with JWST and other telescopes may enable direct imaging of epsilon Eridani b and further study of its properties.

Scientific study

Worlds Next Door. III. Indirect Evidence for Enhanced Atmospheric Metallicity and/or the Presence of Water Clouds in the Nearest Jupiter-analog ε Eri b (external link)