Illustration (Artist’s Impression) of WASP-39 b and Its Star

This illustration shows what exoplanet WASP-39 b could look like, based on current understanding of the planet.

WASP-39 b is a hot, puffy gas giant with a mass 0.28 times Jupiter (0.94 times Saturn) and a diameter 1.3 times greater than Jupiter, orbiting just 0.0486 astronomical units (7,200,000 kilometres) from its star. The star, WASP-39, is fractionally smaller and less massive than the Sun. Because it is so close to its star, WASP-39 b is very hot and is likely to be tidally locked, with one side facing the star at all times.

NASA’s James Webb Space Telescope’s exquisitely sensitive instruments have provided a profile of WASP-39 b’s atmospheric constituents and identified a plethora of contents, including water, sulphur dioxide, carbon monoxide, sodium and potassium.

This illustration is based on indirect transit observations from Webb as well as other space and ground-based telescopes. Webb has not captured a direct image of this planet.

[Image Description: This image shows an artist's impression of the planet WASP-39 b and its star. The planet has a fuzzy orange-blue atmosphere with hints of longitudinal cloud bands below. The left quarter of the planet (the side facing the star) is lit, while the rest is in shadow. The star is bright yellowish-white, with no clear features.]