Warm Gas-Giant Exoplanet WASP-107 b (Artist’s Concept)

This artist’s concept shows what the exoplanet WASP-107 b could look like based on recent data gathered by NASA’s James Webb Space Telescope along with previous observations from Hubble and other space- and ground-based telescopes.

WASP-107 b is a -warm Neptune’ exoplanet orbiting a relatively small and cool star approximately 210 light-years from Earth, in the constellation Virgo. The planet is about 80% of the size of Jupiter in terms of volume, but has a mass less than 10% of Jupiter’s, making it one of the least dense exoplanets known.

WASP-107 b orbits its star at a distance about 5 million miles (0.055 astronomical units, or AU), completing one circuit in 5.72 days. The planet is tidally locked: it rotates at the same rate that it orbits the star, which means that one side is permanently lit, with the other in continuous darkness, so there is no day–night cycle. The orbit of WASP-107 b is slightly elliptical, which means that the gravitational pull between the star and planet changes continuously as the planet moves toward and away from the star during its orbit.

Observations of 0.8- to 12-micron infrared light captured by the NASA/ESA Hubble Space Telescope’s WFC3 (Wide Field Camera 3), and Webb’s NIRCam (Near-Infrared Camera), NIRSpec (Near-Infrared Spectrograph), and MIRI (Mid-Infrared Instrument), suggest that the planet has a relatively large core surrounded by a relatively small mass of hydrogen and helium gas, which has been inflated by tidal heating of the interior.

WASP-107 b has not been directly imaged by any telescope.

[Image description: Illustration of an exoplanet with a hazy blue atmosphere and loose bands of clouds on the black background of space. The right three-quarters of the planet is lit by a star not shown in the illustration. The left quarter is in shadow. The terminator, the boundary between the day and night sides, is gradual, not sharp. The planet is light blue with loose bands of white clouds. The limb of the planet (the edge) has a subtle blue glow.]