The CHEOPS space telescope detects concentric circles of light in rainbow colors at WASP-76b, an exoplanet with iron rain.
Astronomers have discovered for the first time evidence of halos, colorful rainbow-like meteorological phenomena, on an exoplanet (planet outside the solar system), IFL Science reported on April 5. New research published in the journal Astronomy & Astrophysics.
The halo consists of concentric circles of light in rainbow colors – red on the outside and purple on the inside. Although also formed by water droplets bending light, halos differ from rainbows because backscattered light is diffracted between water droplets, rather than being refracted through them. This phenomenon gets its name because it resembles the halo around the heads of saints in medieval paintings.
“There’s a reason why halos have never been seen outside the solar system before. This phenomenon requires very special conditions. First, it requires atmospheric particles with almost perfect, perfect spherical shapes.” completely uniform and stable enough to be observed for long periods of time. The star near the planet needs to shine directly on it, and the observing device – here the CHEOPS space telescope – points in the right direction.” , said lead researcher Olivier Demangeon, astronomer at the Institute of Astrophysics and Space Sciences in Portugal.
Exoplanet WASP-76b is so close to the host star and so hot that it is said to rain iron. This close distance causes one side of WASP-76b to be tidally locked and always facing the host star, called the “day side”, hot up to 2,400 degrees Celsius. The other side of the exoplanet, the “night side”, is always facing outer space and being cooler, but subject to strong winds caused by temperature differences. Near the day-night boundary, the metal evaporated on the day side condenses and falls as iron rain.
More evidence is needed to confirm that the phenomenon observed by the CHEOPS space telescope at WASP-76b is a rare halo. If correct, this phenomenon suggests the presence of clouds made of perfectly spherical water droplets that have existed for at least three years, or that these clouds are constantly being replenished. If the clouds are persistent, WASP-76b’s atmospheric temperature should also be stable over time. This is interesting information, showing stability in an exoplanet that is considered chaotic.
The new discovery also shows that exoplanet experts can study distant worlds to find similar light phenomena, including starlight reflected from liquid lakes and oceans. This is very important in the search for life outside the solar system that humans are conducting.