WASP-107b

WASP-107b is a super-Neptune exoplanet that orbits the star WASP-107. It lies 200 light-years away from Earth in the constellation Virgo. Its discovery was announced in 2017 by a team led by D. R. Anderson via the WASP-South.

Planetary orbit
WASP-107b could not have formed in its current orbit. It likely migrated inward from its birth orbit beyond 1 AU due to interaction with the heavier planet WASP-107c. It is in a retrograde orbit, strongly misaligned with the equatorial plane of the parent star. The misalignment angle is equal to 118°$$. WASP-107c follows a highly eccentric and inclined orbit with a period of 1088$$ days.

Physical characteristics
WASP-107b is a super-Neptune ice giant exoplanet located 200 light years away from Earth in the constellation Virgo. It is roughly the size of Jupiter but less than one-tenth of Jupiter's mass, making it one of the lowest density exoplanets. Its radius is 0.96$$ times Jupiter's, making its atmosphere fluffy, and coupled with transiting a moderately bright K-type star, makes it a target for atmospheric characterization. It is eight times nearer to its star than Mercury is to the Sun and orbits its star every 5.7 days. With a temperature of 500 C, its atmosphere makes it one of the hottest known exoplanets.

Helium was discovered in the planet's atmosphere in 2018, making it the first time helium was discovered on an exoplanet. A follow-up observation with Keck in 2020 showed that the helium absorption extends beyond transit-egress. Extreme ultraviolet radiation from the host star is gradually whittling down the planet's atmosphere, forming a comet-like tail 7 times as long as the radius of the planet.

In November 2023, scientists discovered that its atmosphere contains water vapor and sulfur dioxide. The clouds on this planet are made up of silicates. The James Webb Space Telescope (JWST) revealed groundbreaking findings about exoplanet WASP-107b. Utilizing its Mid-Infrared Instrument (MIRI), European astronomers discovered water vapor, sulfur dioxide, and silicate sand clouds in its atmosphere. This challenges existing models and deepens our understanding of exoplanetary atmospheres, marking a significant milestone in exoplanetary exploration.

In May 2024, groundbreaking new findings about WASP-107b were revealed by the James Webb Space Telescope (JWST). Webb's observations, using its Near-Infrared Camera (NIRCam), Mid-Infrared Instrument (MIRI), and Near-Infrared Spectrograph (NIRSpec), detected water vapor (H2O), methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), sulfur dioxide (SO2), and ammonia (NH3) in the exoplanet's atmosphere. This data, along with the surprisingly low abundance of methane, suggests a hotter interior and a more massive core than previously estimated. Tidal heating, caused by the planet's slightly elliptical orbit, is believed to be the source of the extra internal heat. These findings challenge existing models of exoplanet formation and atmosphere composition, marking a significant leap in our understanding of these distant worlds.