The distant planet Quaoar, named after a creation god in Native American mythology, is creating surprises for astronomers studying it – the ring surrounding it is unusually far from the planet and defies current understanding of how these rings form and exist, reports Reuters .
Quaoar is located beyond Pluto at the far edges of the Solar System in the Kuiper Belt, a massive ring of asteroids and pseudo-planetary celestial bodies that surround the Solar System.
Researchers said on Wednesday that they have detected Saturn-like rings around Quaoar. This planet’s ring, however, goes beyond astronomers’ current understanding of how planetary rings form—it’s much further away than usual.
The distance between the planet and its rings is large enough that fragments of rock and ice could coalesce around a celestial body to form a moon, making it more unlikely that it would remain in ring form.
“A“I basically discovered a ring in a place where its existence shouldn’t be possible,” said astronomer Bruno Morgado of the Valongo Observatory at the Federal University of Rio de Janeiro in Brazil, one of the lead authors of a study published in the scientific journal Nature.
Discovered in 2002, Quaoar is defined as a small planet and has been proposed for “dwarf planet” classification, although it has not yet received formal status from the International Astronomical Union.
Quaoar has a diameter of 1,110 kilometers, which is about one-third the diameter of the Moon and half that of the planet Pluto. In addition to the ring, Quaoar also has a small moon orbiting beyond the rock fragments.
Quaoar is in the Kuiper belt, a distant region of many icy celestial bodies, and orbits at 43 times Earth’s distance from the Sun. By comparison, Neptune orbits at 30 times that distance.
Quaoar’s ring was discovered using ESA’s Cheops orbital telescope. It is made of ice particles and is 4,100 kilometers from Quaoar’s center, with a diameter of 8,200 kilometers.
“Ring systems are formingfrom debris from the planet’s formation process or from debris resulting from the collision with another body captured by the planet. We have no clues now as to when Quaoar’s ring was formed“, said study co-author Isabella Pagano, director of the Catania Observatory.
Unlike other planetary rings, Quaoar’s is located outside the Roche limit – the distance at which a celestial body with an appreciable gravitational field tears apart another smaller nearby body. Fragments of rock and ice outside the Roche limit usually assemble into another larger body.
Saturn has the largest ring system in the Solar System. And the other gas giants – Jupiter, Uranus and Neptune have rings. The rings of these planets are all in the Roche limit.
Editor: Adrian Dumitru