20000 Varuna

20000 Varuna is a big Kuiper belt object (KBO). It could be a dwarf planet. Before it was named Varuna, it had the provisional designation 2000 WR₁₀₆.

20000 Varuna

Hubble Space Telescope image of Varuna
Discovery
Discovered by	R. McMillan (Spacewatch)
Discovery date	28 November 2000
Designations
MPC designation	20000 Varuna
Alternative names	2000 WR106
Minor planet category	TNO (cubewano)[1]
Orbital characteristics
Epoch 14 July 2004 (JD 2453200.5)
Aphelion	6 781.985 Gm (45.335 AU)
Perihelion	6 120.810 Gm (40.915 AU)
Semi-major axis	6 451.398 Gm (43.129 AU)
Eccentricity	0.051
Orbital period	103 440.6 d (283.20 a)
Average orbital speed	4.53 km/s
Mean anomaly	89.673°
Inclination	17.2°
Longitude of ascending node	97.296°
Argument of perihelion	271.631°
Physical characteristics
Dimensions	800 km (avg of thermals)[2] (scalene ellipsoid)?[3][4]
Mass	≈3.7×1020? kg[3][5]
Mean density	0.992 g/cm³[3]
Surface gravity	0.15 m/s²
Escape velocity	0.39 km/s
Sidereal rotation period	0.132 16 d (3.17 h)
Albedo	0.037–0.26[2]
Temperature	≈43–41 K
Spectral type	(moderately red) B-V=0.93 V-R=0.64[6]
Apparent magnitude	19.9 (opposition)[7]
Absolute magnitude (H)	3.7[8]

Varuna is named after the Hindu deity Varuṇa.

Physical characteristics

Varuna completes one rotation in about 3.17 hours (or 6.34 hours, depending on whether the light curve is single or double-peaked). Given the fast rotation, which is not common for objects so big, Varuna is thought to be a stretched spheroid, with a density around 1g/cm³ (close to the density of water).^[4]

The surface of Varuna is somewhat red and small amounts of water ice have been found on its surface.^[9]