James Webb Space Telescope Feed Post

Hot Gas Giant Exoplanet WASP-39 b Transmission Spectrum (NIRSpec)

This transmission spectrum, captured using Webb’s NIRSpec (Near-Infrared Spectrograph) PRISM bright object-time series mode, shows the amounts of near-infrared starlight blocked by the atmosphere of hot gas giant exoplanet WASP-39 b. The spectrum shows clear evidence for water and carbon dioxide, and a variation in temperature between the morning and evening on the exoplanet. New analysis of the transmission spectrum of WASP-39 b builds two different spectra from the stationary day/night boundary on the exoplanet, essentially splitting this terminator region into two semicircles, one from the evening, and the other from the morning. Data reveals the evening as significantly hotter, a searing 1,450 degrees Fahrenheit (800 degrees Celsius), and the morning a relatively cooler 1,150 degrees Fahrenheit (600 degrees Celsius). The blue and yellow lines are a best-fit model that takes into account the data, the known properties of WASP-39 b and its star (e.g., size, mass, temperature), and assumed characteristics of the atmosphere. Read more: science.nasa.gov/missions/webb/nasas-webb-investigates-et... Credits: Illustration: NASA, ESA, CSA, Ralf Crawford (STScI) Image Description: Graphic titled “Hot Gas-Giant Exoplanet WASP-39 b Transmission Spectrum: Morning Terminator vs. Evening Terminator.” There are two sets of Webb data points, with error bars and a best-fit model for each, on a graph. Amount of Light Blocked is labeled on the y-axis versus Wavelength of Light in microns on the x-axis. The y-axis ranges from less light blocked at bottom to more light blocked at top. The x-axis ranges from 2.0 to 5.2 microns. The data consists of 38 points plotted in yellow and green, and the best-fit model for each are jagged yellow and green lines with several broad peaks and valleys. In the same place for both lines, two peaks are labeled (from left to right) as the signatures of Water H2O and Carbon Dioxide CO2. Image & Description by NASA