ALT The graphic shows the transmission spectrum of the hot gas giant exoplanet WASP-39 b, captured using Webb's NIRSpec Bright Object Time-Series Spectroscopy mode, and is titled accordingly. An illustration of the planet and its star is in the background. The vertical y axis is labeled “amount of light blocked” and runs from 2.00 percent (less light blocked) to 2.35 percent (more light blocked). The x axis is labeled “wavelength of light” and ranges from 3.00 microns to 5.6 microns. The data points are plotted as white circles with gray error margin bars running through the circles. A curvy blue line represents a best-fit model. A prominent peak in the blue line is labeled “Carbon Dioxide, CO2,” indicating the presence of carbon dioxide in the exoplanet. This peak is centered around 4.3 microns and has a y value of between 2.25 and 2.30 percent of light blocked. The baseline is between 2.10 and 2.17 percent.
