Transmission Spectrum - WASP-107 b (NIRSpec)

This transmission spectrum, captured using Webb’s NIRSpec (Near-Infrared Spectrograph), shows the amounts of different wavelengths (colours) of near-infrared starlight blocked by the atmosphere of the gas-giant exoplanet WASP-107 b .

The spectrum was made by observing the planet-star system for about 8.5 hours before, during, and after the transit as the planet moved across the face of the star.

By comparing the brightness of light filtered through the planet’s atmosphere (transmitted light) to unfiltered starlight, it is possible to calculate the amount of each wavelength that is blocked by the atmosphere. Since each molecule absorbs a unique combination of wavelengths, the transmission spectrum can be used to constrain the abundances of various gases.

This spectrum shows clear evidence for water (H2O), carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), and sulphur dioxide (SO2) in the planet’s atmosphere, allowing researchers to estimate its interior temperature and the mass of its core.

[Image description: Transmission Spectrum of NIRSpec bright object time-series spectroscopy showing a graph of Amount of Light Blocked vs. Wavelength of Light, with peaks for water, carbon dioxide, methane, sulphur dioxide, and carbon monoxide labelled.]