Quaoar, the celestial object at the edge of the Solar System that challenges a 19th century theory

Quaoar is a celestial object

located in the confines of the Solar System and

, but it has been discovered that it does have one, when what should have formed around it would be a satellite, according to a theory that has been in force since 1850.

A team with the participation of the Instituto de Astrofísica de Andalucía (IAA-CSIC, southern Spain) describes this discovery in

, which calls into question what is known as

, the theory of the maximum distance at which, around an object , fragments of dust and ice can accumulate to create rings.

Until now, only rings around

, the planetoid Clarico and the dwarf planet Haumea were known.

In these cases, those structures are within the Roche limit.

Quaoar is a large trans-Neptunian object half the size of Pluto that orbits our star at 43 times the distance between Earth and the Sun and is orbited by a small moon called Weywot, about 80 km in radius.

Now it has been discovered that it also has

, and that it has a "unique and surprising property": its large radius of 4,100 kilometers, which corresponds to about 7.4 radii of Quaoar, points out the Spanish Higher Council for Scientific Research (CSIC), in a statement.

Photographic illustration of the largest known Kuiper belt objects, including Quaoar.

The presence of a ring at a distance of almost seven and a half times the radius of its dwarf planet opens up a mystery for astronomers to solve

, indicates the European Space Agency (ESA).

Edouar Roche developed his theory in the mid-19th century and, until now, this was what had been observed: all known rings lie within or near the boundary of their respective bodies, but Quaoar's occupies an orbit where it should have formed. a small moon in just a few decades.

"As a result of our observations, the classical notion that dense rings only survive within the Roche limit of a planetary body needs to be thoroughly revised," according to Giovanni Bruno of the Catania Astrophysical Observatory, Italy.

The IAA-CISC researcher, José Luis Ortiz, recalls that when they saw the possible existence of the ring, they thought that "it could take many years to conclusively prove this circumstance, but finally" they achieved it "in a few years thanks to international efforts". with the participation of 59 researchers from all over the world

Early results from the study suggest that Quaoar's frigid temperatures may help prevent icy particles from sticking together, but more research is needed, the ESA says.

Quaoar is a large trans-Neptunian object half the size of Pluto.

AFP PHOTO/ NASA

The discovery of that ring triggered numerous numerical studies and local simulations of self-gravitation were developed.

The collision laws classically used to describe Saturn's rings resulted in rapid buildups, which would favor the formation of a satellite in that region.

However, the more elastic collision laws obtained in the laboratory at low temperatures showed the opposite: the post-impact velocities between the particles remain high enough to escape each other's attractions and eventually overcome their tendency to clump together. .

Thus, while the Roche criterion seems robust to explain how tidal forces disrupt the formation of a satellite to form a ring;

in the opposite process, the accumulation of particles in a satellite, implies

, explains the CSIC.

However, there are still unknowns about this dwarf planet, since the ring is at a distance from Quaoar in which the particles that form it take three times more time to go around it than it takes the object itself to rotate around it. itself.

This is a phenomenon already observed in Haumea and it is believed that it also occurs in Cariclo, "so there seems to be a common pattern in the formation of dense rings," says Ortiz.

The discovery of the Quaoar ring arose from observations between 2018 and 2021 from a robotic telescope in Namibia (HESS project);

the Gran Telescopio Canarias (La Palma, Spanish Atlantic archipelago);

the CHEOPS Space Telescope (ESA) and Australian amateur stations.

EFE

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