(455502) 2003 UZ413 (provisional designation 2003 UZ413) is a trans-Neptunian object (TNO) with an absolute magnitude of 4.38.[5] It is in a 2:3 orbital resonance with Neptune, thus it is classified as a plutino.[3] There are indications it may be dense enough to be a dwarf planet. It was given the minor planet number 455502 on 22 February 2016.[11]
 Hubble Space Telescope image of 2003 UZ413 taken in 2008 | |
| Discovery[1] | |
|---|---|
| Discovered by | M. E. Brown D. L. Rabinowitz C. A. Trujillo |
| Discovery date | 21 October 2003 |
| Designations | |
| 2003 UZ413 | |
| TNO[2] · plutino[3][4][a] | |
| Orbital characteristics[2] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 2 | |
| Observation arc | 63.25 years (23103 days)\ |
| Earliest precovery date | 29 July 1954 |
| Aphelion | 47.968 AU (7.1759 Tm) |
| Perihelion | 30.241 AU (4.5240 Tm) |
| 39.104 AU (5.8499 Tm) | |
| Eccentricity | 0.22667 |
| 244.54 yr (89317.3 d) | |
| 113.43° | |
| 0° 0m 14.51s / day | |
| Inclination | 12.04911° |
| 135.930° | |
| 145.00° | |
| Physical characteristics | |
| Dimensions | 650+1 −175 km (upper limit)[5] 472+122 −25 km (lower limit)[5] |
| Mass | ≈3×1020 kg[b] |
Mean density | 2.29–3.00 > ρ >0.72 g/cm3[6] 2.64 g/cm3[7] |
| 4.13±0.05 h[6][8] 4.14 h[2] | |
| 0.075+0.076 −0.006 (lower limit)[5] 0.151+0.025 −0.064 (upper limit)[5] | |
| V–R=0.45±0.04[5] BB taxon (blue/neutral)[7][9][c] V−R=0.46±0.06 R−I=0.37±0.06[9] | |
| 21[10] | |
| 4.38±0.05[5] 4.3 (assumed)[2] | |
2003 UZ413 has been observed 79 times over 15 oppositions, with precovery images back to 27 July 1954.[2]
Orbit and rotation
2003 UZ413 is in a 2:3 resonance with Neptune, which means that when it makes two revolutions around the Sun, Neptune makes exactly three.[3]
The object rotates very fast. In fact, with a period of about 4.13 hours, it is the fastest rotator known in the Kuiper belt after Haumea.[6][8]
Physical characteristics
The mean diameter of 2003 UZ413 is estimated to be 650+1
−175 km, assuming a low albedo.[5]
Given its rapid rotation, it must have a density higher than 0.72 g/cm3.[6] Stable Jacobi ellipsoids with an axis ratio of a/b ≥ 1.13±0.03, as implied by its light-curve amplitude of Δm = 0.13±0.03, exist for densities in the range of 2.29−3.00 g/cm3.[6] The Johnston's Archive settles on 2.64 g/cm3,[7] the centre of the latter range; for a 600 km equivalent spheroid body, this would equate to a mass of approximately 3.0×1020 kg. The extremely high estimated density (in contrast to any known similarly sized TNO)[12] would make it virtually certain that this object is a dwarf planet, but confirmation would require additional observation to refine the size and light curve details, preferably with discovery of a satellite to determine its mass.
In visible light, this object is neutral or slightly red in color and has a flat, featureless reflectance spectrum.[8]