Overview
- A Max Planck–led team reported on April 22, 2026 that new JWST data for the nearby gas giant Epsilon Indi Ab show less ammonia than models predict.
- Using JWST’s MIRI coronagraph, which blocks starlight to reveal faint planets, the team compared images at 10.6 μm and 11.3 μm to estimate ammonia in the atmosphere.
- The weaker ammonia signal, paired with the planet’s faint mid-infrared output, matches a picture of thick, patchy water-ice clouds high in the atmosphere.
- Epsilon Indi Ab orbits about four times farther from its star than Jupiter does from the Sun, has roughly 7.6 Jupiter masses with a similar diameter, and holds a temperature near 200–300 K.
- The study in Astrophysical Journal Letters urges cloud-inclusive models, and the team plans more JWST observations as NASA’s Roman telescope is expected to detect reflective ice clouds directly.