Hot gas giant exoplanet WASP-43 b (artist’s concept)

An international team of researchers has successfully used the NASA/ESA/CSA James Webb Space Telescope to map weather on the hot gas-giant exoplanet WASP-43 b.

This artist’s concept shows what the hot gas giant exoplanet WASP-43 b could look like. WASP-43 b is a Jupiter-sized planet that orbits a star roughly 280 light-years away, in the constellation Sextans. The planet orbits at a distance of about 0.014 AU (1.3 million miles), completing one circuit in about 19.5 hours. Because it is so close to its star, WASP-43 b is probably tidally locked: its rotation rate and orbital period are the same, such that one side faces the star at all times.

Temperature measurements based on the amount of 5- to 12-micron mid-infrared light emitted by the planet show that the nightside is probably covered in thick high clouds. Because it is too hot for liquid water to exist, the clouds are probably made of tiny mineral grains instead of water droplets.

Spectroscopy measurements indicate the presence of water vapour on both the dayside and nightside. A surprising lack of methane on the nightside suggests that strong winds are mixing atmospheric gases around the planet.

This illustration is based on new data gathered by Webb’s Mid-Infrared Instrument (MIRI) as well as previous observations from other ground- and space-based telescopes, including Hubble and Spitzer. Webb has not captured any images of the planet.

Learn more here.

[Image description: Illustration of an exoplanet on a black background. The planet is large, in the foreground on the left. The planet is various shades of blue, with wisps of white scattered throughout.]

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