Quaoar

Quaoar, also called 50000 Quaoar, is a ringed dwarf planet in the Kuiper belt. The Kuiper belt is a faraway area filled with icy objects past the planet Neptune.

Astronomers Chad Trujillo and Michael Brown found Quaoar in 2002 at the Palomar Observatory. Quaoar is about half the size of Pluto. It has a width of about 1,100 kilometers (680 miles). Its surface looks reddish and is made of crystalline water ice. It also has substances called tholins and traces of frozen methane.

One exciting thing about Quaoar is that it has two thin rings orbiting around it. These rings are found outside Quaoar's Roche limit. This is a place where rings were thought to not stay stable. Scientists think Quaoar's special shape, the pull from its moons, and its very cold environment help keep the rings in place. Quaoar has a moon named Weywot. There might be another moon, but it is not confirmed. This faraway world gives us useful information about how objects in the outer solar system formed and move.

History

Quaoar was discovered on 4 June 2002 by American astronomers Chad Trujillo and Michael Brown at the Palomar Observatory in the Palomar Mountain Range in San Diego County, California. They saw a dim object moving among the stars in pictures taken at the observatory. This object looked brighter than expected for something so far away, suggesting it might be very large.

After the discovery, more old pictures of the sky were found to help learn its path. These pictures were from telescopes that had taken photos of the sky in past years. The discovery of Quaoar was announced in October 2002. It was given a special number, 50000, because of its large size. Later, it was named Quaoar after a creation force from the mythology of the Tongva people, who live in the area where the discovering institute is located.

Orbit and classification

Quaoar orbits the Sun at an average distance of 43.7 AU. It takes about 289 years to complete one full orbit. Its orbit is nearly circular, ranging from 42 AU to 45 AU from the Sun. Because of this, Quaoar does not come close enough to Neptune to be significantly affected by its gravity.

Quaoar is a trans-Neptunian object, meaning it orbits beyond Neptune. It is classified as a classical Kuiper belt object.

Physical characteristics

Quaoar is a large, round object in space called a dwarf planet. It is located in the Kuiper Belt, a region beyond the planet Neptune. Quaoar is about half the size of Pluto, measuring around 1,100 kilometers (680 miles) across.

Scientists have studied Quaoar and found that it has a dark surface. Observations also show that Quaoar might have small amounts of methane and other chemicals on its surface. Because of these materials, Quaoar could possibly have a very thin atmosphere, though it is very faint and not very dense.

Satellites

Weywot

Main article: Weywot

Quaoar has one confirmed moon called Weywot. It was found in 2006 and is named after a sky god from Tongva stories. Weywot goes around Quaoar at a distance of about 13,300 km and takes 12.4 days to finish one circle. It is a dark object about 200 km across.

Second moon

In 2025, scientists saw a star get dimmer when Quaoar was nearby. This did not look like what they expected from Weywot or Quaoar's rings, so they think there might be another, smaller moon. If it exists, this moon would be at least 30 km wide but much smaller than Weywot. Special watching of stars may help prove if it is really there some day.

Rings

Astronomers found that Quaoar, a dwarf planet far from Earth, has two thin rings of icy particles around it. The first ring, called Q1R, was discovered in 2023 using telescopes when Quaoar passed in front of a star. This ring is very far from Quaoar and changes in thickness around its circle. The second ring, Q2R, was found later and is closer to Quaoar than the first ring. Both rings stay in place because of special patterns in how they move compared to Quaoar's spin.

Exploration

Scientists have thought about sending space trips to visit Quaoar. One plan uses a planet named Jupiter to help a spacecraft get to Quaoar. This trip could take about 13.6 years. In 2016, a camera on the New Horizons spacecraft took pictures of Quaoar from far away. Future space missions, like Interstellar Probe and China’s Shensuo, might also visit Quaoar. Scientists are interested in Quaoar because it might have special features, like a thin atmosphere and icy volcanoes.