Extended Data Fig. 5. The transit spectrum of WSP-39b as determined by our independent analysis using JWST’s NIRCam instrument (top) and the respective differences between our results (bottom).

Top: transmission spectra from our reductions when including additional data on the blue and red edges (now spanning 2.405–4.055 µm). This demonstrates the large error bars and diverging data points near the edges of the NIRCam bandpass in the LW spectroscopic channel. Bottom: the differences in retrieved transmission spectra by subtracting the Eureka! spectrum from the other three reduced spectra shown in the top panel. This shows the strong agreement between the spectra; however, we do note minor disagreements at shorter wavelengths that we attribute to differences in the treatment of limb-darkening effects within the individual fitting methods.