Establish whether the low-SNR JWST feature is ε Eridani b

Establish whether the low-signal-to-noise feature detected in the second JWST/NIRCam epoch at the predicted position of ε Eridani b is genuine planetary emission rather than a noise or reduction artifact, using additional comparable-sensitivity NIRCam epochs.

Background

A faint feature in the second JWST/NIRCam epoch lies essentially at the position predicted from the radial-velocity and astrometric orbit fit. Although the chemical-equilibrium atmospheric model yields a comparatively high posterior significance for interpreting the feature as the planet, the direct image feature itself has only approximately 2–3σ significance and the paper explicitly declines to claim a detection.

The authors state that two further NIRCam epochs with comparable signal-to-noise would test whether the feature recurs at the planet’s predicted location. If it does not recur, the clear-atmosphere, equilibrium-chemistry interpretation would be ruled out.

References

The only satisfying answer to this question would be to observe the system again with JWST/NIRCam. Two more epochs at a comparable SNR would confirm whether this feature is the planet. If the feature is not there, then we can finally rule out that the planet is in equilibrium with a clear atmosphere.

— An Updated Model for Epsilon Eridani b and Prospects for Imaging with the Roman Coronagraph  (2609.19131 - Llop-Sayson et al., 16 Sep 2026) in Section 4.1.1, “Is the low-SNR feature the planet?”; reiterated in Section 7, Conclusions