Until now, it was thought that planets with rings They all had characteristics in common with Saturn. The composition of both the planet and the rings may be different, but they are all more or less the same distance from each other. However, a new study shows that we were wrong, since a dwarf planet has been discovered in the Solar System whose rings are located much further away.
This is interesting for two reasons. First, because ringed planets are very rare in our planetary system. Finding one more, albeit a dwarf planet, is really interesting. And, on the other hand, because that distance between the rings and the planet raises that, perhaps, pre-existing ideas about the origin of these structures could be wrong.
Their study could greatly help us better understand how ringed planets, including Saturn, originate. And all thanks to HiPERCAMan instrument developed by scientists at the University of Sheffield and installed in the Gran Telescopio de Canarias.
What do we know about planets with rings?
Until now, two minor planets and four ringed planets were known in the Solar System. The first are chariklolocated between the orbits of Saturn and Uranus, and Haumea, beyond Neptune. As for the planets with known rings, they are Saturn, Uranus, Neptune and Jupiter. They are all gas planets, although their rings have very different compositions. While on Saturn water ice predominates, on the rest silicates or icy dust are more common.
The number of rings on each planet is also different. But there is something that does not vary much: the distance. In all of them, the rings are more or less at the same distance. In the case of Saturn, the planet with the best studied rings, it is three planetary radii and in the rest approximately the same.
This is because the rings are held in place by meeting before the Roche limit. This is the minimum distance that one object can keep orbiting another and maintaining its shape thanks to its own gravity, without being disintegrated by the other’s tidal forces. The theory of scientists until now was that the tidal forces of the planets keep rings in place for a time. If they were beyond the Roche limit, the material would organize differently and eventually form moons around the planet.
Not everyone is like Saturn
In addition to the aforementioned planets, we now know that there is another dwarf planet that has them: quaoar. Its rings are very faint, so they cannot be seen directly in images taken by telescopes.
However, thanks to HiPERCAM its presence could be detected by changes in the light from a background star. It was seen that, while it orbited around the Sun, the dwarf planet blocked its light momentarily, but repeatedly. The pattern of those blocks corresponded to the presence of rings. However, the rings would be at a distance of seven planetary spokesmuch further than expected.
This changes everything. We now know that ringed planets could maintain these structures in some unknown way. Also Saturn and the others. It will be necessary to continue studying them to know more. But at least we have rediscovered something that is increasingly imperative in science. We must be very careful before taking something for granted.