Fig. 2. The transit spectrum of WASP-39b as measured from JWST’s NIRCam instrument.
The coloured points with 1σ uncertainties depict our independent analyses of the spectroscopic LW channel (2.420–4.025 µm) and photometric SW channel (2.0–2.2 µm) with their respective throughputs shown in grey. All analyses agree with the broadband Spitzer point (black circle, 3.2–4.0 µm). The broad feature centred at 2.8 µm spans 2.5 scale heights (∼2,000 km) and is due primarily to water vapour within WASP-39b’s atmosphere. We note the consistency between analyses in the fine structure.