5145 Pholus ("FOE luss") is a Centaur in an eccentric orbit, with a perihelion near the orbit of Saturn and aphelion near the orbit of Neptune. It is believed to have originated as a Kuiper belt object. Spacewatch is a project at the University of Arizona that specializes in the study of minor planets, and including various types of asteroids and comets. ... David Lincoln Rabinowitz (born 1960) is a professor at Yale University researching the Kuiper belt and the outer solar system. ... January 9 is the 9th day of the year in the Gregorian calendar. ... 1992 is a leap year starting on Wednesday of the Gregorian calendar. ... The provisional designation of comets and asteroids are similar to each other: they both follow a pattern set in 1925 by the Minor Planet Center of the IAU. Historical designations At first, astronomers strove to assign symbols to the minor planets: 1 Ceres a stylized sickle 2 Pallas a lozenge... Minor planets, or planetoids are minor bodies of the solar system orbiting the sun that are larger than meteoroids (the largest of which might be taken to be around 10 meters or so across) but smaller than major planets (Mercury having a diameter of about 4880 km). ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... May 10 is the 130th day of the year in the Gregorian Calendar (131st in leap years). ... 2005 is a common year starting on Saturday of the Gregorian calendar and is the current year. ... (This page refers to eccitricity in astrodynamics. ... In geometry, the semi-major axis (also semimajor axis) a applies to ellipses and hyperbolas. ... The astronomical unit (AU or au or a. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... The orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body. ... Inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit and is the angular distance of the orbital plane from the plane of the reference (usually planets equator or the ecliptic), stated in degrees. ... A degree (or in full a degree of arc), usually symbolized °, is a measurement of plane angle, representing 1/360 of a full rotation. ... The Longitude of the ascending node () is one of the orbital elements used to specify the orbit of an object in space. ... The argument of the perihelion is one of the orbital elements describing the orbit of a planet. ... In the study of orbital dynamics the mean anomaly is a measure of time, specific to the orbiting body p, which is a multiple of 2π radians at and only at periapsis. ... Mass is a property of physical objects that, roughly speaking, measures the amount of matter they contain. ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... It has been suggested that Law of universal gravitation be merged into this article or section. ... In physics, for a given gravitational field and a given position, the escape velocity is the minimum speed an object without propulsion, at that position, needs to have to move away indefinitely from the source of the field, as opposed to falling back or staying in an orbit within a... In astronomy, a rotation period is the time an astronomical object takes to complete one revolution around its rotation axis. ... An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standardized distance away. ... The albedo is a measure of reflectivity of a surface or body. ... Temperature is the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... Atmospheric characteristics Surface pressure ≫100 MPa Hydrogen - H2 80% ±3. ... Artists rendering of the Kuiper Belt and more distant Oort cloud. ...

It was discovered by David L. Rabinowitz, then of the University of Arizona's Spacewatch Project, and named by him after Pholus, the brother of the mythological Chiron, after which 2060 Chiron was named. David Lincoln Rabinowitz (born 1960) is a professor at Yale University researching the Kuiper belt and the outer solar system. ... The University of Arizona (UA) is a land-grant institution of higher learning located in Tucson, Arizona. ... Spacewatch is a project at the University of Arizona that specializes in the study of minor planets, and including various types of asteroids and comets. ... In Greek mythology, Pholus was a wise centaur and friend of Herakles. ... In Greek mythology, Chiron (hand) — sometimes spelled Cheiron — was held as the superlative centaur over his brethren. ... 2060 Chiron (IPA: ) is an object in the outer Solar system with an orbit between those of Saturn and Uranus and a radius of 71±5 km [1]. Although it was initially classified as an asteroid, later dispute arose as to whether it was an asteroid or actually a comet. ...

Pholus was the second Centaur type asteroid to be discovered and was quickly found to be the reddest object observed to date in the Solar System, for which it has been occasionally nicknamed "Big Red". The color has been speculated to be due to organic compounds on its surface. (Wilson, et al., 1994) Unlike the first Centaur, 2060 Chiron, Pholus has shown no signs of cometary activity. Guido Reni, Abduction of Deianira, 1620-21 In Greek mythology, the centaurs (Greek: Κένταυροι) are a race part human and part horse, with a horses body and a human head and torso. ... Presentation of the Solar system (not to scale). ... 2060 Chiron (IPA: ) is an object in the outer Solar system with an orbit between those of Saturn and Uranus and a radius of 71±5 km [1]. Although it was initially classified as an asteroid, later dispute arose as to whether it was an asteroid or actually a comet. ...

The diameter of Pholus is estimated to be 185±16 km [2].

References

• Wilson PD, Sagan C, Thompson WR (1994). "The organic surface of 5145 Pholus: constraints set by scattering theory". Icarus 107:288-303. PMID 11539180