83982 Crantor (), '' prov. designation'': , is 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 ...

in a 1:1

resonance Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillatin ...

with

Uranus Uranus is the seventh planet from the Sun. Its name is a reference to the Greek god of the sky, Uranus (mythology), Uranus (Caelus), who, according to Greek mythology, was the great-grandfather of Ares (Mars (mythology), Mars), grandfather ...

, approximately in diameter. It was discovered on 12 April 2002, by astronomers of 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 ...

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

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 ...

was named for

Crantor Crantor ( el, Κράντωρ, ''gen''.: Κράντορος; died 276/5 BC) was a Greek philosopher and scholarch (leader) of the Old Academy, probably born around the middle of the 4th century BC, at Soli in Cilicia (modern-day Turkey). Life C ...

from Greek mythology.

Orbit and classification

''Crantor'' orbits the Sun at a distance of 14.0–24.9 AU once every 85 years and 10 months (31,342 days). Its orbit has a semi-major axis of 19.5 AU, a moderate

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-Centre (geometry), center, in geometry * Eccentricity (g ...

of 0.28, 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 13 ° 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 ...

. The minor planet was first observed on a

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 ...

taken by the

Sloan Digital Sky Survey The Sloan Digital Sky Survey or SDSS is a major multi-spectral imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project began in 2000 a ...

on 19 March 2001. One night later, 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 with an observation by the

Air Force Maui Optical Station The Air Force Maui Optical and Supercomputing observatory is an Air Force Research Laboratory (AFRL) operating location at Haleakala Observatory on Maui, Hawaii, with a twofold mission (). First, it conducts the research and development mission ...

(AMOS) at Haleakala Observatory on the island of Hawaii, more than a year prior to its official discovery observation by NEAT.

Co-orbital with Uranus

''Crantor'' was first suggested as a possible co-orbital of Uranus in 2006. The body follows a complex, transient

horseshoe orbit In celestial mechanics, a horseshoe orbit is a type of co-orbital configuration, co-orbital motion of a small orbiting body relative to a larger orbiting body. The osculating orbit, osculating (instantaneous) orbital period of the smaller body re ...

around Uranus. Classical horseshoe orbits include the

Lagrangian points In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium for small-mass objects under the influence of two massive orbiting bodies. Mathematically, this involves the solution of th ...

, , and , but Crantor's horseshoe orbit also brings it near Uranus. The motion of Crantor is mainly controlled by the influence of the Sun and Uranus, but Saturn has a significant destabilizing effect. The precession of the nodes of Crantor is accelerated by Saturn, controlling its evolution and short-term stability.

Naming

This

was named after

, a

Lapith The Lapiths (; grc, Λαπίθαι) are a group of legendary people in Greek mythology, whose home was in Thessaly, in the valley of the Peneus and on the mountain Pelion. Mythology Origin The Lapiths were an Aeolian tribe who, like the Myr ...

from

Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...

. He was killed in the battle between the Lapiths and the Centaurs by Demoleon, who tore off Crantor's chest and left shoulder with a tree trunk that he had thrown at

Theseus Theseus (, ; grc-gre, Θησεύς ) was the mythical king and founder-hero of Athens. The myths surrounding Theseus his journeys, exploits, and friends have provided material for fiction throughout the ages. Theseus is sometimes describe ...

, who ducked out of the way (centaur Demoleon is not to be confused with Trojan warrior

Demoleon In Greek mythology, Demoleon (Ancient Greek: Δημολέων) was a Trojan warrior, son of Antenor and Theano. His father was a counselor to King Priam and his mother was a priestess of Athena. Family Demoleon was the brother of Crino, Acamas ...

, ''see 18493 Demoleon''). The official naming citation was published 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 15 December 2005 ().

Physical characteristics

Water ice has been detected on ''Crantor'' with a confidence of more than 3 σ (99.7%).

Rotation period

A fragmentary 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 ''Crantor'' was obtained from photometric observations at 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 m ...

in Granada, Spain . Lightcurve analysis gave a

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 13.94 hours with a brightness amplitude of 0.14

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 ...

().

Diameter and albedo

According to the observations by 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 ...

with its PACS instrument, ''Crantor'' measures kilometers in diameter and its surface has an

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 0.121. The ''Collaborative Asteroid Lightcurve Link'' assumes an albedo of 0.10 and derives a diameter of 61.59 kilometers based on 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 9.17.

References

External links

This is an image of Crantor taken by the SDSS telescope on 16APR2002 when it was 13.1au from Earth /Fermats Brother

Atlas of the mean motion resonances in the Solar System
Gallardo, Tabaré (2006)

(Jun 18, 2013)

– Minor Planet Center
Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Observatoire de Genève, Raoul Behrend

– Minor Planet Center * * {{DEFAULTSORT:Crantor Centaurs (small Solar System bodies) 083982 083982 Named minor planets 20020412