WASP-76b is an exoplanet that revolves around the star WASP-76 about 640 light years away in the Pisces constellation.
The star WASP-76 has an apparent magnitude of 9.5, an absolute magnitude of 4.1, and is a spectral F7 type star with a surface temperature of 6250K.
The star has a mass about 1.5 times that of the sun and a radius about 1.7 times that of the sun.
WASP-76b is the only planet orbiting WASP-76 and it is classified as a hot jupiter.
The exoplanet was discovered by the transit method in 2013.
Its mass is about 0.92 times that of Jupiter, but the powerful radiation from the main star expands the atmosphere and the radius is about 1.83 times that of Jupiter, making it a low-density planet.
The largest radius of its orbit is about 0.033 AU (5 million km) and its orbit lasts around 1.8 days.
Its temperature is 2700K on the day-side and 1800K on the night-side; it is tidally locked.
In 2020, observations at the Paranal Observatory with the Very Large Telescope (VLT) revealed that the day-side atmosphere was rich in iron vapor.
A strong wind blows on the surface because the temperature difference between the day-side and the night-side is close to 1000K. The wind and the rotation carry iron vapor from the day-side to the night-side, which causes cooling. It is thought that this causes condensation, which becomes rain.
（References）
- Exoplanet.eu “Planet WASP-6b” <http://exoplanet.eu/catalog/WASP-76_b/> (2020/3/27)
- EXOPLANET EXPLORATION “WASP-76 b” <https://exoplanets.nasa.gov/exoplanet-catalog/1833/wasp-76-b/> (2020/3/27)
- SPACE.com “Molten iron rain falls through the skies of scorching-hot exoplanet” <https://www.space.com/alien-planet-iron-rain-WASP-76b.html> (2020/3/27)
- ESO “ESO Telescope Observes Exoplanet Where It Rains Iron” <https://www.eso.org/public/news/eso2005/> (2020/3/27)
