(303775) 2005 QU182 - 14th Largest TNO? 4th Largest SDO?

2005 QU182 is a trans-Neptunian object and is possibly the 14th largest TNO and 4th largest SDO currently known.

Discovery

2005 QU182 is discovered on August 30, 2005 by Michael E. Brown, Chadwick A. Trujillo and David Lincoln Rabinowitz.

2005 QU182 has precovery images back to 1974.

Stats

Estimated Diameter: 730 km (530 - 1186 km)
Aphelion: 190.75 AU
Perihelion: 37.01 AU
Semi-major axis: 113.88 AU
Orbital Period: 1215 years
Rotation period: ? hours
Date discovered: 2005.8.30
Satellite: ?
Classification: TNO, SDO

Orbit

2005 QU182 takes over 1,200 years to orbit the Sun. Of the dwarf planets and known dwarf-planet candidates, only Sedna is known to have a longer orbit around the Sun.

2005 QU182 came to perihelion in 1971, and is currently 49 AU from the Sun.

How big is it?

2005 QU182 is so far away in the outer solar system that we don't know for sure how large it is. Because all we see is a dot of light, which is sunlight reflected off the surface of the TNO. But we don't know if the object is bright because it is large or if it is bright because it is highly reflective or both.

Dwarf-planet candidate

2005 QU182 has a bright absolute magnitude of 3.5. This qualifies it as one of the largest dwarf-planet candidates. As of August 2011, Mike Brown lists it as highly likely a dwarf planet.