(455502) 2003 UZ413
, also written as 2003 UZ413, is a trans-Neptunian object (TNO) with an absolute magnitude of 4.38. It is in a 2:3 orbital resonance with Neptune, thus it is classified as a plutino. 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. Orbit and rotation. is in a 2:3 resonance with Neptune, which means that when it makes two revolutions around the Sun, Neptune makes exactly three. 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. Physical characteristics. The mean diameter of is estimated to be , assuming a low albedo. Given its rapid rotation, it must have a density higher than . Stable Jacobi ellipsoids with an axis ratio of , as implied by its light-curve amplitude of , exist for densities in the range of . The "Johnston's Archive" settles on , the centre of the latter range; for a equivalent spheroid body, this would equate to a mass of approximately . The extremely high estimated density (in contrast to any known similarly sized TNO) 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.