(

provisional designation Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been cal ...

) is a

trans-Neptunian object A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet in the Solar System that orbits the Sun at a greater average distance than Neptune, which has a semi-major axis of 30.1 astronomical units (au). Typically ...

(TNO) with an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it ...

of 4.38. It is in a 2:3

orbital resonance In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly, this relationsh ...

with Neptune, thus it is classified as a

plutino In astronomy, the plutinos are a dynamical group of trans-Neptunian objects that orbit in 2:3 mean-motion resonance with Neptune. This means that for every two orbits a plutino makes, Neptune orbits three times. The dwarf planet Pluto is the l ...

. There are indications it may be dense enough to be a

dwarf planet A dwarf planet is a small planetary-mass object that is in direct orbit of the Sun, smaller than any of the eight classical planets but still a world in its own right. The prototypical dwarf planet is Pluto. The interest of dwarf planets to ...

. It was given the

minor planet number A formal minor-planet designation is, in its final form, a number–name combination given to a minor planet (asteroid, centaur, trans-Neptunian object and dwarf planet but not comet). Such designation always features a leading number (catalog or ...

455502 on 22 February 2016. has been observed 79 times over 15 oppositions, with precovery images back to 27 July 1954.

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 , discoverer = , discovered = , earliest_precovery_date = March 22, 1955 , mpc_name = (136108) Haumea , pronounced = , adjectives = Haumean , note = yes , alt_names = , named_after = Haumea , mp_category = , orbit_ref = , epoc ...

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 ellipsoid A Jacobi ellipsoid is a triaxial (i.e. scalene) ellipsoid under hydrostatic equilibrium which arises when a self-gravitating fluid body of uniform density rotates with a constant angular velocity. It is named after the German mathematician Carl Gu ...

s 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

, 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.

Notes

References

External links

2003 UZ413 Precovery Images
* {{DEFAULTSORT:455502 Plutinos Discoveries by the Palomar Observatory Possible dwarf planets 20031021