, '' prov. designation'': , 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, ...

from the outermost region of the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...

. It was discovered on 14 November 2002, by astronomers with the

Near-Earth Asteroid Tracking Near-Earth Asteroid Tracking (NEAT) was a program run by NASA and the Jet Propulsion Laboratory, Astronomical survey, surveying the sky for near-Earth objects. NEAT was conducted from December 1995 until April 2007, at Ground-based Electro-Optica ...

program at the

Palomar Observatory Palomar Observatory is an astronomical research observatory in San Diego County, California, United States, in the Palomar Mountain Range. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...

in California, United States. This

resonant trans-Neptunian object In astronomy, a resonant trans-Neptunian object is a trans-Neptunian object (TNO) in mean-motion orbital resonance with Neptune. The orbital periods of the resonant objects are in a simple integer relations with the period of Neptune, e.g. 1:2, 2 ...

is a member of the plutino population, locked in a 2:3 resonance with

Neptune Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times ...

. The object is likely of primordial origin with a heterogeneous surface and a notably reddish color ( RR) attributed to the presence of

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...

and

tholin Tholins (after the Greek (') "hazy" or "muddy"; from the ancient Greek word meaning "sepia ink") are a wide variety of organic compounds formed by solar ultraviolet or cosmic ray irradiation of simple carbon-containing compounds such as carbon ...

s. It has a poorly defined

rotation period The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...

of 6.8 hours and measures approximately in diameter, too small to be a

dwarf planet candidate The number of dwarf planets in the Solar System is unknown. Estimates have run as high as 200 in the Kuiper belt and over 10,000 in the region beyond. However, consideration of the surprisingly low densities of many large trans-Neptunian objects ...

. , it has not yet been named.

Orbit and classification

' belongs to the plutino population, named after its largest member,

Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the S ...

. Plutinos are

s, that are locked in a stable 2:3 mean-motion resonance with

, orbiting the Sun twice for every three orbits Neptune does. They form a significantly large part of the inner

Kuiper belt The Kuiper belt () is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times ...

, as hundreds of these objects have already been discovered. This

minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...

orbits the Sun at a distance of 27.9–50.4 AU once every 245 years and 3 months (89,562 days;

semi-major axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the long ...

of 39.18 AU). Its orbit has an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-center, in geometry * Eccentricity (graph theory) of a v ...

of 0.29 and an

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

of 16 ° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic again ...

. On 29 June 2001, it came to perihelion and has since been moving away from the Sun. Due to

precovery In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of an object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This happens mos ...

images recovered from the

Digitized Sky Survey The Digitized Sky Survey (DSS) is a digitized version of several photographic astronomical surveys of the night sky, produced by the Space Telescope Science Institute between 1983 and 2006. Versions and source material The term Digitized Sky S ...

, the body's

observation arc In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...

begins already in October 1990, or 12 years prior to its official discovery observation by astronomers with the

at Palomar.

Numbering and naming

' was numbered (55638) by the

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function ...

on 16 February 2003 (). , it has not been named. According to the established

naming conventions A naming convention is a convention (generally agreed scheme) for naming things. Conventions differ in their intents, which may include to: * Allow useful information to be deduced from the names based on regularities. For instance, in Manhatta ...

for plutinos, it will be named after a mythological figure from the

underworld The underworld, also known as the netherworld or hell, is the supernatural world of the dead in various religious traditions and myths, located below the world of the living. Chthonic is the technical adjective for things of the underworld. ...

Physical characteristics

Rotation period

The

of ' is poorly defined and has ambiguous results with multiple alternative period solutions in between 4.90 and 10 hours. In December 2002, a rotational

lightcurve In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...

of this object was obtained from photometric observations by astronomers from the

Sierra Nevada Observatory The Sierra Nevada Observatory ( es, Observatorio de Sierra Nevada; OSN; code: J86) is located at Loma de Dilar (2896 m altitude) in the Sierra Nevada mountain range, in the province of Granada, Spain; established in 1981. It is operated and main ...

in Spain. Lightcurve analysis gave a poorly defined period of hours with a brightness variation of

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

(). Two years later in December 2004, it was revisited by the same astronomers, obtaining another poorly defined period of hours with an amplitude of magnitude (). Other observations by Sheppard only determined an amplitude of less than 0.06 magnitude ().

Diameter and albedo

In 2010, observations with the

Herschel Space Telescope The Herschel Space Observatory was a space observatory built and operated by the European Space Agency (ESA). It was active from 2009 to 2013, and was the largest infrared telescope ever launched until the launch of the James Webb Space Teles ...

, using its PACS instrument to measure the object's thermal radiation, gave a mean-diameter of with a relatively high

albedo Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body ...

of for an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

of . In addition, an

asteroid occultation An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks ...

s on 3 December 2015, gave a best-fit ellipse dimension of () with an poor quality rating of 1. These timed observations are taken when the asteroid passes in front of a distant star. The ''Collaborative Asteroid Lightcurve Link'' assumes a more regular albedo for a distant object of 0.10 and hence estimates a larger diameter of 297 kilometers.

Color and composition

In the visible light, ' has a featureless reflectance spectrum. It is very red in color (RR), with a color index of 1.080 and 0.71, in the B–V and V−R passband filters, respectively. The

near-infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of Light, visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from ...

spectrum of ' is flat with two distinct absorption bands of water ice at 1.5 and 2.0

μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

. There is the third feature near 2.3 μm of unclear origin. The spectral behavior of this object is similar to

5145 Pholus 5145 Pholus is an eccentric centaur in the outer Solar System, approximately in diameter, that crosses the orbit of both Saturn and Neptune. It was discovered on 9 January 1992 by American astronomer David Rabinowitz (uncredited) of UA's Space ...

, a

centaur A centaur ( ; grc, κένταυρος, kéntauros; ), or occasionally hippocentaur, is a creature from Greek mythology with the upper body of a human and the lower body and legs of a horse. Centaurs are thought of in many Greek myths as being ...

. Observations with the

Very Large Telescope The Very Large Telescope (VLT) is a telescope facility operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each with a primary mirror 8.2 m across, ...

revealed that ' has a heterogeneous surface—the amount of different ices and non-ice components depends on the observed area. Among the probable surface materials are water ice (4–19%),

ice (10–12%) and various

s, photochemically altered organic compounds, also found on

Triton Triton commonly refers to: * Triton (mythology), a Greek god * Triton (moon), a satellite of Neptune Triton may also refer to: Biology * Triton cockatoo, a parrot * Triton (gastropod), a group of sea snails * ''Triton'', a synonym of ''Triturus' ...

and

Titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fictiona ...

. The redder areas are generally associated with the presence of methanol ice. The surface of ' appears to be primordial in origin.

References

External links

List of Transneptunian Objects
''Minor Planet Center'' * {{DEFAULTSORT:2002 VE95 055638 055638 20021114