English: 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% the size of Jupiter in terms of volume, but has a mass less than 10% of Jupiter, making it one of the least dense exoplanets known. WASP-107 b orbits its star at a distance of 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, with 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 Hubble’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 due to tidal heating of the interior. WASP-107 b has not been directly imaged by any telescope.

NASA, ESA, CSA, Ralf Crawford (STScI)