The rainbow, one of the most captivating optical spectacles on our planet, has been sighted only once on Venus. However, the latest data suggests that a similar phenomenon, known as the “glory effect”, has been detected on an exoplanet called WASP-76, located 637 light years away. This remarkable discovery has been possible thanks to the European satellite Cheops, a mission of the European Space Agency (ESA) dedicated to the characterization of exoplanets.
The extrasolar “glory,” characterized by concentric rings of colored lights, has been observed projecting directly from the infernal atmosphere of WASP-76b, a gas giant that shares similarities with Jupiter.
According to data collected by Cheops, this unique phenomenon occurs due to the scorching heat and intense sunlight on the illuminated side of the exoplanet, as well as the perpetual darkness on its night side. This effect, commonly observed on Earth, has only been previously recorded on the planet Venus. If the results are confirmed, it will mark the first time it has been detected outside our Solar System.
Olivier Demangeon, astronomer at the Portuguese Institute of Astrophysics and Space Sciences and lead author of the study, explains: “This phenomenon requires very particular conditions, such as almost perfectly spherical and uniform atmospheric particles, as well as a precise alignment between the star, the exoplanet and the observer.
ESA exoplanet expert Matthew Standing emphasizes the extraordinary magnitude of this discovery, highlighting the complexities of WASP-76b, a distant world where temperatures reach 2,400 degrees Celsius and are thought to rain molten iron.
Since its discovery in 2013, WASP-76b has been the subject of meticulous attention, revealing a hellish panorama with extreme temperatures and an unusual atmospheric cycle. Additionally, the data collected for this study comes from various space missions, including TESS, Hubble and Spitzer, carried out by ESA and NASA.
Although the “glory” effect shares visual similarities with the rainbow, it is important to note that they are different phenomena. While the rainbow is formed by the refraction of light through water droplets, the “glory” arises when light passes through a narrow opening, such as clouds or fog, and diffracts, creating concentric rings of colors.
This fascinating discovery not only expands our understanding of atmospheric phenomena on distant exoplanets, but also underlines the astonishing diversity that exists in the vast cosmos beyond our own star system.