Overview

• JWST spectra show sharp 3.3‑micron emission interpreted as solar‑excited methane fluorescence above Makemake’s surface.
• Models fit two viable sources: an ultra‑tenuous atmosphere near 40 K with roughly 10 picobars surface pressure, or transient plumes releasing a few hundred kilograms per second.
• The detection makes Makemake only the second trans‑Neptunian object with confirmed gas, following Pluto.
• Earlier stellar occultations indicated no substantial global atmosphere, though a thin one could have escaped detection, consistent with the new result.
• The research is posted on arXiv with an Astrophysical Journal Letters paper in press, and the team is seeking higher‑resolution JWST follow‑ups to resolve the mechanism.