![]() Artist's impression of exoplanet WASP-107b. [1] | |
Discovery | |
---|---|
Discovered by | D. R. Anderson et al. |
Discovery date | 2017 |
WASP-South | |
Orbital characteristics | |
0.0566 ± 0.0017 AU (8,470,000 ± 250,000 km) [2] | |
Eccentricity | 0.06 ± 0.04 [2] |
5.7214742 d [2] | |
Star | WASP-107 |
Physical characteristics | |
0.96±0.03 RJ [2] | |
Mass | 0.096±0.005 [2] MJ |
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. [3] Its discovery was announced in 2017 by a team led by D. R. Anderson via the WASP-South. [4]
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°+38
−19. [5] WASP-107c follows a highly eccentric and inclined orbit with a period of 1088+15
−16 days. [2]
WASP-107b is a super-Neptune ice giant exoplanet roughly the size of Jupiter but less than one-tenth of Jupiter's mass, making it one of known lowest density-exoplanets. [2] This is unusual provided that the mean temperature of its upper atmosphere is only 500 °C (932 °F), much lower than that of similarly inflated exoplanets. [6] Its highly extended and low density atmosphere coupled with transiting a moderately bright orange dwarf star makes it an attractive target for atmospheric characterization via transmission spectroscopy. [7] It is about eight times nearer to its star than Mercury is to the Sun and orbits its star every 5.7 days. [3]
Helium was discovered in the planet's atmosphere in 2018, making it the first time helium was discovered on an exoplanet. [8] A follow-up observation with Keck in 2020 showed that the helium absorption extends beyond transit-egress. [9] 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. [10] [11]
In November 2023, scientists discovered that its atmosphere contains water (H2O) vapour and sulfur dioxide (SO2). The clouds on this planet are made up of silicates. [12] [13] The data, along with the unexpectedly low abundance of methane (CH4), 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. [14]
In September 2024 it was revealed that there is an east-west asymmetry in the atmospheric properties (e.g, climate, cloud structure) of WASP-107b, which previously had not been expected for planet of its kind. [6]
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