Quaoar
Low-resolution Hubble Space Telescope image of Quaoar and its moon Weywot, February 2006 | |
| Discovery | |
|---|---|
| Discovered by | |
| Discovery site | Palomar Observatory |
| Discovery date | 4 June 2002 |
| Designations | |
| (50000) Quaoar | |
| Pronunciation | /ˈkwɑːwɑːr/, /ˈkwɑː.oʊ.ɑːr/ |
Named after | Qua-o-ar / Kwawar (deity of the Tongva people) |
| 2002 LM60 (provisional designation) | |
| |
| Adjectives | Quaoarian |
| Symbol | (mostly astrological) |
| Orbital characteristics | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 3 | |
| Observation arc | 65.27 yr (23,839 d) |
| Earliest precovery date | 25 May 1954 |
| Aphelion | 45.488 AU (6.805 Tm) |
| Perihelion | 41.900 AU (6.268 Tm) |
| 43.694 AU (6.537 Tm) | |
| Eccentricity | 0.04106 |
| 288.83 yr (105,495 d) | |
| 301.104° | |
| 0° 0m 12.285s / day | |
| Inclination | 7.9895° |
| 188.927° | |
| 11 February 2075 ±17 days | |
| 147.480° | |
| Known satellites | 1 confirmed (Weywot) 1 unconfirmed |
| Physical characteristics | |
| Dimensions | 1,166.6 × 1,110.6 × 1,020.0 km (± 5.2 × 2.0 × 2.0 km) |
| 1,097.6±2.2 km (volume equivalent) | |
| 3.79×106 km2 | |
| Volume | 6.92×108 km3 |
| Mass | (1.212±0.005)×1021 kg (Quaoar only) |
Mean density | 1.751±0.013 g/cm3 |
Equatorial surface gravity | 0.31 m/s2 at poles to 0.24 m/s2 at longest axis |
Equatorial escape velocity | 0.56 km/s at poles to 0.53 km/s at longest axis |
| 17.6788±0.0004 h | |
| 12.6° to ecliptic (if coplanar with rings) | |
North pole right ascension | 259.5°±0.2° (rings) |
North pole declination | +55.0°±0.2° (rings) |
| Temperature | ≈ 44 K |
| 19.0 | |
| 2.737±0.008 2.4 (assumed) | |
| 40.4±1.8 milliarcseconds | |
Quaoar (minor-planet designation: 50000 Quaoar) is a ringed dwarf planet in the Kuiper belt, a band of icy planetesimals beyond Neptune. It has a slightly ellipsoidal shape with an average diameter of 1,100 km (680 mi), about half the size of the dwarf planet Pluto. The object was discovered by American astronomers Chad Trujillo and Michael Brown at Palomar Observatory on 4 June 2002. Quaoar has a reddish surface made of crystalline water ice, tholins, and traces of frozen methane.
Quaoar has two thin rings orbiting outside its Roche limit, which defies theoretical expectations that rings outside the Roche limit should be unstable. Quaoar has one moon named Weywot and another unnamed moon that has not yet been confirmed. It is believed that Quaoar's elongated shape, gravitational influence of its moons, and extremely cold temperature help keep its rings stable.