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Dwarf Planet Candidate (90377) Sedna

EBriggs's picture

 

Sedna is the Inuit goddess of the sea and the mother of all sea creatures. She rewards the people of the land with food from the sea. Without her blessing, hunts fail and the people starve. She is thus one of the most important figures in Inuit legend. 
 
The discoverers consider Sedna to be a dwarf planet, since it likely satisfies criteria. It is large enough (1200 to 1600 km diameter) to have likely achieved hydrostatic equilibrium, and it is not a moon, but it has not cleared its orbit. As Sedna has no known moons, determining its mass is very difficult. However, if the above estimates for its diameter are coupled with Pluto's density of 2.0 g/cm3, the resultant estimated mass range is 1.8–4.3 x 1021 kg.
 
Sedna has the longest orbital period of any known large object in the Solar System, calculated at around 11,400 years. Its orbit is extremely eccentric, with an aphelion estimated at 937 AU and a perihelion at about 76 AU, the most distant perihelion ever observed for any Solar System object. At its discovery it was approaching perihelion at 89.6 AU from the Sun, and was the most distant object in the Solar System yet observed.
 
Reference: MPC 52771
Name: 
Sedna
Number: 
90377
Designation: 
2003 VB12
Disc. Date: 
2003-11-14
Discoverer: 
Brown, M.E., Trujillo, C.A. & Rabinowitz, D.
Disc. Place: 
Palomar