Saturn’s atmosphere is heating up. And this has nothing to do with changes in its distance from the Sun.
The secret has spent 40 years hidden in plain sight. It took the insights of Lotfi Ben-Jaffel’s team, from the Paris Institute of Astrophysics in France, to reveal it.
The researchers used observations of Saturn made by the Hubble Space Telescope and the Cassini space probe (now decommissioned), as well as observations made by the Voyager 1 and 2 space probes and the International Ultraviolet Explorer (IUE) satellite. , the latter also already out of service.
The study authors have found that Saturn’s vast ring system is heating the planet’s upper atmosphere. This is an unprecedented phenomenon in the solar system. This unexpected interaction between Saturn and its rings could provide a technique for predicting whether planets around other stars also have ring systems similar to Saturn’s.
Telltale evidence that the rings heat the upper part of Saturn’s atmosphere is excess ultraviolet radiation, seen as a spectral line of hot hydrogen in Saturn’s atmosphere. This increase in radiation means that something is polluting and heating the upper atmosphere from the outside.
This composite image shows Saturn’s set of Lyman-alpha lines, due to hydrogen, which is present in excess in the planet’s spectrum. An image captured by Hubble in the near ultraviolet band (the part of the ultraviolet segment of the electromagnetic spectrum closest to the segment of visible light) is used as reference. This image was obtained in 2017, during Saturn’s summer in its northern hemisphere. The rings appear much darker than the body of the planet because they reflect much less ultraviolet sunlight. Above the rings and the dark equatorial region, the Lyman-alpha bulge appears as an extended latitudinal band (30 degrees) that is 30 percent brighter than the surrounding regions. A small fraction of the southern hemisphere appears between the rings and the equatorial region, but it is dimmer than the northern hemisphere. North of the bulge region (upper right of image), the disk’s brightness gradually decreases as a function of latitude, toward the bright auroral region shown here for reference (not to scale). A dark spot within the aurora region represents the imprint of the planet’s axis of rotation. The measurements from which the image has been made were made between 1980 and 2017. (Image: NASA / ESA / Lotfi Ben-Jaffel (IAP & LPL))
The most plausible explanation for the phenomenon is that icy particles from the ring raining down on Saturn’s atmosphere cause this warming. This could be promoted by the impact of micrometeorites, particle bombardment from the solar wind, solar ultraviolet radiation, or electromagnetic forces that pick up electrically charged dust. All this occurs under the additional influence of Saturn’s gravitational field, which drags the particles towards the planet. When NASA’s Cassini probe plunged into Saturn’s atmosphere at the end of its mission in 2017, it measured atmospheric components and confirmed that many particles in the atmosphere fall from the rings.
The study is titled “The Enigmatic Abundance of Atomic Hydrogen in Saturn’s Upper Atmosphere.” And it has been published in the academic journal The Planetary Science Journal. (Source: NCYT de Amazings)