Nereid

Discovery
Discovered by:	Gerard P. Kuiper[1]
Discovery date:	May 1, 1949
Orbital characteristics
Periapsis:	1,353,600 km (0.00905 AU)
Apoapsis:	9,623,700 km (0.06433 AU)
Semi-major axis:	5,513,400 km (0.03685 AU)
Eccentricity:	0.7512
Orbital period:	360.1362 d
Avg. orbital speed:	1.12 km/s
Max. orbital speed:	2.95 km/s
Min. orbital speed:	0.42 km/s
Inclination:	5.07° (to Ecliptic) 32.55° (to Neptune's equator) 7.232° (to the local Laplace plane)
Satellite of:	Neptune
Physical characteristics
Mean radius:	170 km
Mass:	3.1×1019 kg[citation needed]
Mean density:	1.5 g/cm3
Rotation period:	0.48 d (11 h 31 min)[2]
Albedo:	0.14
Temperature:	~51 K mean (estimate)

Nereid (IPA: [ˈnɪ.ɹi.ɪd], IPA: [ˈnɛ.ɹi.ɪd], Greek Νηρηίδα), or Neptune II, is a moon of Neptune. Original caption: Nereid, the last satellite of Neptune to be discovered before Voyagers recent discoveries, was first seen by Gerard Kuiper in 1949. ... Gerard Peter Kuiper, born Gerrit Pieter Kuiper (December 7, 1905 – December 23, 1973) was a Dutch-American astronomer. ... May 1 is the 121st day of the year in the Gregorian calendar (122nd in leap years). ... 1949 (MCMXLIX) was a common year starting on Saturday (the link is to a full 1949 calendar). ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... A kilometer (Commonwealth spelling: kilometre), symbol: km is a unit of length in the metric system equal to 1,000 metres (from the Greek words χίλια (khilia) = thousand and μέτρο (metro) = count/measure). ... 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. ... A kilometer (Commonwealth spelling: kilometre), symbol: km is a unit of length in the metric system equal to 1,000 metres (from the Greek words χίλια (khilia) = thousand and μέτρο (metro) = count/measure). ... The astronomical unit (AU or au or a. ... The semi-major axis of an ellipse In geometry, the term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae. ... km redirects here. ... The astronomical unit (AU or au or a. ... (This page refers to eccitricity in astrodynamics. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... A day is any of several different units of time. ... 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. ... 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. ... 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 in general is the angle between a reference plane and another plane or axis of direction. ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... The Laplace plane is defined as the mean plane occupied by the orbit of a satellite during a precession cycle. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... Atmospheric characteristics Surface pressure ≫100 MPa Hydrogen - H2 80% ±3. ... Unsolved problems in physics: What causes anything to have mass? The U.S. National Prototype Kilogram, which currently serves as the primary standard for measuring mass in the U.S. Mass is the property of a physical object that quantifies the amount of matter and energy it is equivalent to. ... The U.S. National Prototype Kilogram, which currently serves as the primary standard for measuring mass in the U.S. It was assigned to the United States in 1889 and is periodically recertified and traceable to the primary international standard, The Kilogram, held at the Bureau International des Poids et... In physics, density is mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is... In astronomy, a rotation period is the time an astronomical object takes to complete one revolution around its rotation axis. ... Albedo is the ratio of reflected to incident electromagnetic radiation power. ... Fig. ... The Kelvin scale is a thermodynamic (absolute) temperature scale where absolute zero—the lowest possible temperature where nothing could be colder and no heat energy remains in a substance—is defined as zero kelvin (0 K). ... Not to be confused with the NATO phonetic alphabet, which has also informally been called the “International Phonetic Alphabet”. For information on how to read IPA transcriptions of English words, see IPA chart for English. ... Not to be confused with the NATO phonetic alphabet, which has also informally been called the “International Phonetic Alphabet”. For information on how to read IPA transcriptions of English words, see IPA chart for English. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... Atmospheric characteristics Surface pressure ≫100 MPa Hydrogen - H2 80% ±3. ...

Nereid was discovered on 1 May 1949 by Gerard P. Kuiper, who proposed the name in the report of his discovery. It is named after the Nereids, sea-nymphs of Greek mythology. May 1 is the 121st day of the year in the Gregorian calendar (122nd in leap years). ... 1949 (MCMXLIX) was a common year starting on Saturday (the link is to a full 1949 calendar). ... Gerard Peter Kuiper, born Gerrit Pieter Kuiper (December 7, 1905 – December 23, 1973) was a Dutch-American astronomer. ... In Greek mythology, the Nereids (NEER-ee-eds) are blue-haired sea nymphs, the fifty daughters of Nereus and Doris. ... The bust of Zeus found at Otricoli (Sala Rotonda, Museo Pio-Clementino, Vatican) Greek mythology is the telling of stories created by the ancient Greeks, concerning their gods and heroes, the nature of the world and their own cult and ritual practices. ...

It was the outermost of Neptune's known moons for a long time (Halimede through Neso have since taken that honour), and is the third largest, with a diameter of 340 km. Its orbit averages 5,513,400 km in radius, but is highly eccentric and varies from 1,353,600 to 9,623,700 kilometres. For a long time this was the most highly eccentric orbit of any known satellite in the solar system, but it has recently been superseded by Bestla (moon), a recently discovered moon of Saturn. The unusual orbit suggests that it may be a captured asteroid or Kuiper belt object, or possibly that it was perturbed during the capture of Neptune's largest moon Triton. Very little else is known of Nereid. Halimede is a retrograde irregular satellite of Neptune. ... Neso, also known as Neptune XIII, is the outermost irregular natural satellite of Neptune. ... m. ... In astrodynamics, under standard assumptions any orbit must be of conic section shape. ... Major features of the Solar System (not to scale; from left to right): Pluto, Neptune, Uranus, Saturn, Jupiter, the asteroid belt, the Sun, Mercury, Venus, Earth and its Moon, and Mars. ... Bestla, or Saturn XXXIX (provisional designation S/2004 S 18) is a natural satellite of Saturn. ... Note: This article contains special characters. ... 253 Mathilde, a C-type asteroid. ... Artists rendering of the Kuiper Belt and hypothetical more distant Oort cloud. ... Triton (trye-tÉ™n, IPA: , Greek Τρίτων), or Neptune I, is the planet Neptunes largest moon. ...

Nereid was too far to be properly imaged by the Voyager 2 probe when it visited the Neptune system in 1989. Photos sent back show only its highly irregular shape as no surface features could be seen at the resolution available. Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... Technicians work on the Ulysses space probe. ... 1989 (MCMLXXXIX) was a common year starting on Sunday of the Gregorian calendar. ...

A simulated view of Nereid with Neptune in the distance. The surface details are fictional.

Image File history File links Download high resolution version (1280x948, 76 KB) Simulation of Nereid orbiting Neptune. ... Image File history File links Download high resolution version (1280x948, 76 KB) Simulation of Nereid orbiting Neptune. ... A computer simulation or a computer model is a computer program that attempts to simulate an abstract model of a particular system. ...

References