Epsilon Indi Ab
Cold gas giant orbiting epsilon-indi-a at about four times Jupiter’s distance from the Sun. As of 2026 it is one of the closest true Jupiter analogues directly imaged in mid-infrared by jwst (src-jwst-ice-clouds-exoplanet-2026-04).
Key parameters
- Mass: ~7.6 Jupiter masses
- Diameter: ~1 Jupiter radius
- Temperature: 200-300 K (warmer than Jupiter’s ~140 K due to residual formation heat)
- Orbital separation: ~4× Jupiter’s distance from the Sun
JWST 2026 atmosphere result
elisabeth-matthews et al. (max-planck-institute-for-astronomy) used jwst’s MIRI coronagraph at 11.3 μm and 10.6 μm to constrain ammonia abundance. Observed NH₃ came in below model predictions, and the team’s preferred explanation is patchy water-ice-clouds analogous to high-altitude cirrus on Earth — a feature absent from most exoplanet-atmosphere-models. The nancy-grace-roman-space-telescope coronagraph is positioned as the next instrument capable of detecting reflected light from such clouds.