We are all familiar with light rain, heavy rain, hail, thunder even acid rain. But, ever heard of raining iron from the skies!
Astronomers have detected a surprise, unique weather phenomenon occurring in an exoplanet outside a solar system. The exoplanet, named WASP-76B, is said to have been witnessing iron rain when the metal vapour condenses into clouds.
The exoplanet WASP-76B, discovered in 2016, is about 390 light-years away from Earth and is located in Pisces constellation. This exoplanet is a hot giant gas like Jupiter and belongs to category of ‘Hot Jupiters’. An exoplanet is a planet situated outside our solar system.
According to the researchers, WASP-76B experiences extreme weather conditions, with average temperatures of around 1,700°C. Just like the Moon, this exoplanet orbits close to its host star and is tidally locked, meaning only one of its sides is facing the star at all times. Therefore, at daytime temperatures climb up to 2,400°C—near to the boiling point of many metals.
The team of researchers led by David Ehrenreich discovered the evidence of metallic rainfall. While observing the exoplanet’s atmosphere from the Very Large Telescope (VLT) in Chile, the researchers saw the presence of iron at the transition of day to night. However, to their surprise, the metal was not seen during the transition of night to day. The scientists, therefore, went on to analyse the chemical variations between day and night on the planet.
David Ehrenreich, a researcher at the University of Geneva and the first author of the article explains that the only explanation possible for not seeing iron vapour at dawn is that it rains iron on the dark side of this exoplanet.
During the day time, when the temperatures hits up to 2,400°C, the molecules separate into atoms and the iron evaporates into the atmosphere to form metallic clouds. The clouds with vapourised iron are then driven at strong winds at a speed of about 16,000kmph to cause rain.