NationMaster - Encyclopedia: Neptune's natural satellites

Neptune has thirteen known moons. The largest by far is Triton, discovered by William Lassell just seventeen days after the discovery of Neptune itself. It took about one hundred years to discover the second, Nereid. Image File history File links Voyager_2_Neptune_and_Triton. ... Image File history File links Voyager_2_Neptune_and_Triton. ... Adjectives: Neptunian Atmosphere Surface pressure: (?)â‰«(?) 100 kPa : is asked the pressure at the cloud level. ... Triton (trye-tÉ™n, IPA: , Greek Î¤ÏÎ¯Ï„Ï‰Î½), or Neptune I, is the planet Neptunes largest moon. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... Atmospheric characteristics Surface pressure â‰«100 MPa Hydrogen - H2 80% Â±3. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... Triton (trye-tÉ™n, IPA: , Greek Î¤ÏÎ¯Ï„Ï‰Î½), or Neptune I, is the planet Neptunes largest moon. ... William Lassell (June 18, 1799 â€“ October 5, 1880) was a British astronomer, born in Bolton, Lancashire, England. ... Nereid (IPA: , IPA: , Greek ÎÎ·ÏÎ·Î¯Î´Î±), or Neptune II, is a moon of Neptune. ...

Unusual orbits

Triton orbits Neptune on a circular but retrograde orbit. While retrograde orbits are common among distant irregular satellites, Triton is a unique case of retrograde moon so close to its planet. Direct motion is the motion of a planetary body in a direction similar to that of other bodies within its system, and is sometimes called prograde motion. ...

The third largest moon of Neptune, Nereid follows a prograde but the most eccentric orbit among the moons of the solar system, being at its apocenter more than seven times further from the planet than at its pericenter. Nereid (IPA: , IPA: , Greek ÎÎ·ÏÎ·Î¯Î´Î±), or Neptune II, is a moon of Neptune. ... (This page refers to eccitricity in astrodynamics. ... A diagram of Keplerian orbital elements. ...

Two natural satellites discovered in 2002 and 2003, Psamathe and Neso, have the largest orbits of any natural satellites discovered in the Solar system to date. They take 25 years to orbit Neptune at an average of 125 times the distance between Earth and the Moon. For album titles with the same name, see 2002 (album). ... 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Psamathe (sam-a-thee, Greek Î¨Î±Î¼Î±Î¸ÎµÎ¹Î±, Latin PsamathÄ“) is an irregular natural satellite of Neptune. ... Neso, also known as Neptune XIII, is the outermost irregular natural satellite of Neptune. ...

Theories of origin

It is likely that Neptune's inner satellites are not the original bodies that formed with Neptune but accreted rubble from the havoc that was wreaked after Triton's capture. Triton's original captured orbit would have been highly eccentric, and caused chaotic perturbations in the orbits of the original inner Neptunian satellites, caussing them to collide and become reduced to a rubble disc. Only after Triton's orbit became circularised did some of the rubble disc re-accrete into the present-day satellites ^[1]. Triton (trye-tÉ™n, IPA: , Greek Î¤ÏÎ¯Ï„Ï‰Î½), or Neptune I, is the planet Neptunes largest moon. ...

The mechanism of the Triton’s capture have been the subject of a few theories over the years. The most recent postulates that Triton was captured in a three body encounter. In this scenario, Triton is the surviving member of a binary object¹ disrupted by the encounter with Neptune.^[2].

Numerical simulations show that another moon discovered in 2002, Halimede has had a high probability of collision with Nereid during the lifespan of the system.^[3] As both moons appear to have similar (grey) colours, the satellite could be a fragment of Nereid.^[4] Halimede is a retrograde irregular satellite of Neptune. ...

¹Binary objects, gravitational association of two objects, are quite common among Trans-Neptunian Objects (>10%; the most known is Pluto -Charon) and less so among the asteroids (e.g. Ida and Dactyl). A trans-Neptunian object (TNO) is any object in the solar system with all or most of its orbit beyond that of Neptune. ... Adjectives: Plutonian Atmosphere Surface pressure: 0. ... Charon (shair-É™n or kair-É™n (key), IPA , Greek Î§Î¬ÏÏ‰Î½), discovered in 1978, is, depending on the definition employed, either the largest moon of Pluto or one member of a double dwarf planet with Pluto being the other member. ... It has been suggested that minor planet be merged into this article or section. ... NASA image of 243 Ida. ... 243 Ida (left) and Dactyl (right), as photographed by the Galileo spacecraft. ...

The natural satellites

The Neptunian moons are listed here by orbital period, from shortest to longest. Triton, which is not only massive enough for its surface to have collapsed into a spheroid, but is comparable in size to our own moon, is highlighted in purple. Irregular (captured) moons are shown in grey; prograde in light grey and retrograde in dark grey. (Triton is also thought to be captured.) This article or section does not cite its references or sources. ... In mathematics, a spheroid is a quadric surface in three dimensions obtained by rotating an ellipse about one of its principal axes. ...

^‡ Negative orbital periods indicate a retrograde orbit around Neptune (opposite to the planet's rotation) A simulated view of Naiad orbiting Neptune with The Sun in the distance. ... A simulated view of Thalassa orbiting Neptune. ... A simulated view of Despina orbiting Neptune Despina (des-pee-na or des-pye-na; Latin DespÅ“na from Greek Î”ÎµÏƒÏ€Î¿Î¯Î½Î·) is the third known moon of Neptune. ... Image File history File links No higher resolution available. ... A simulated view of Galatea orbiting Neptune Galatea (gal-a-tee-a, Greek Î“Î±Î»Î±Ï„ÎµÎ¯Î±) is the fourth known moon of Neptune, named after Galatea, one of the Nereids of Greek legend. ... A simulated view of Larissa orbiting Neptune Larissa (la-ris-a, Greek Î›Î¬Ïá¿‘ÏƒÎ±) is the fifth of Neptunes known moons. ... Image File history File links Larissa_1. ... Atmospheric pressure 0 kPa Proteus (proe-tee-us, Greek Î ÏÏ‰Ï„ÎÎ±Ï‚) is one of Neptunes moons. ... Download high resolution version (727x726, 31 KB)Photo of Netptunes satellite Proteus taken by Voyager 2 (large version). ... Triton (trye-tÉ™n, IPA: , Greek Î¤ÏÎ¯Ï„Ï‰Î½), or Neptune I, is the planet Neptunes largest moon. ... Download high resolution version (1024x796, 150 KB)A color mosaic of Triton, Neptunes moon (large). ... Nereid (IPA: , IPA: , Greek ÎÎ·ÏÎ·Î¯Î´Î±), 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. ... Halimede is a retrograde irregular satellite of Neptune. ... Sao is a prograde irregular satellite of Neptune. ... Laomedeia, or Neptune XII, is a prograde irregular satellite of Neptune. ... Psamathe (sam-a-thee, Greek Î¨Î±Î¼Î±Î¸ÎµÎ¹Î±, Latin PsamathÄ“) is an irregular natural satellite of Neptune. ... Neso, also known as Neptune XIII, is the outermost irregular natural satellite of Neptune. ... The astronomical unit (AU or au or a. ... This article is about retrograde motion. ...

Irregular satellites

The diagram illustrates the orbits of Neptune’s irregular satellites discovered so far. The eccentricity of the orbits is represented by the yellow segments (extending from the pericentre to the apocentre) with the inclination represented on Y axis. The satellites above the X axis are prograde, the satellites beneath are retrograde. The X axis is labelled in Gm (million km) and the fraction of the Hill sphere's (gravitational influence) radius (~116 Gm for Neptune). Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... This diagram shows the orbits of Saturns irregular satellites surrounding the planet like a swarm. ... A diagram of Keplerian orbital elements. ... This article is about retrograde motion. ... Prograde motion is the motion of a planetary body in a direction similar to that of other bodies within its system, and is sometimes called direct motion, especially in astrology. ... A gigametre (American spelling: gigameter) (symbol: Gm) is a unit of length equal to 109 metres. ... A Hill sphere approximates the gravitational sphere of influence of one astronomical body in the face of perturbations from another heavier body around which it orbits. ...

Given the similarity of their orbits, it was suggested that Neso and Psamathe could have a common origin in the break-up of a larger moon.^[5] Neso, also known as Neptune XIII, is the outermost irregular natural satellite of Neptune. ... Psamathe (sam-a-thee, Greek Î¨Î±Î¼Î±Î¸ÎµÎ¹Î±, Latin PsamathÄ“) is an irregular natural satellite of Neptune. ...

Triton, the biggest moon following a retrograde but a quasi-circular orbit, also conjectured to be a captured satellite, is not shown. Nereid, on a prograde but very eccentric orbit is believed to be scattered during Triton's capture.^[6]

Naming notes

Some asteroids share the same names as moons of Neptune: 74 Galatea, 1162 Larissa. See also Name conflicts of solar system objects. It has been suggested that minor planet be merged into this article or section. ... 74 Galatea (gal-a-tee-a) is a large Main belt asteroid. ... Although in principle every named body in the Solar system ought to have a distinct name, due to a variety of circumstances, there are several real or apparent name conflicts between different solar system bodies. ...

Note that Triton did not have an official name until the twentieth century. Although the name was suggested in 1880 by Camille Flammarion, it did not come into common use until at least the 1930s. Usually, it was simply known as "the satellite of Neptune" (the second satellite, Nereid, was not discovered until 1949). (19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s As a means of recording the passage of time, the 20th century was that century which lasted from 1901–2000 in the sense of the Gregorian calendar (1900–1999... Year 1880 (MDCCCLXXX) was a leap year starting on Thursday (link will display the full calendar). ... Camille Flammarion Camille Flammarion (February 26, 1842 â€“ June 3, 1925) was a French astronomer and author. ... 1930 (MCMXXX) was a common year starting on Wednesday (link is to a full 1930 calendar). ... Nereid (IPA: , IPA: , Greek ÎÎ·ÏÎ·Î¯Î´Î±), or Neptune II, is a moon of Neptune. ... 1949 (MCMXLIX) was a common year starting on Saturday (the link is to a full 1949 calendar). ...

References

Categories: Neptune's moons | Neptune | Planetary satellites Matthew J. Holman is a Smithsonian Astrophysicist and lecturer at Harvard University. ... JJ Kavelaars is a Canadian astronomer who was part of a team that discovered several moons of Saturn, Uranus, and Neptune. ... Brett J. Gladman is a Canadian astronomer and an Associate Professor at the University of British Columbias Department of Physics and Astronomy, in Vancouver, British Columbia. ... Brian G. Marsden is an astronomer, the longtime director of the Minor Planet Center. ... Matthew J. Holman is a Smithsonian Astrophysicist and lecturer at Harvard University. ... Scott S. Sheppard is an astronomer based at the Institute for Astronomy at the University of Hawaii. ... David C. Jewitt is a Professor of astronomy at the University of Hawaii Institute for Astronomy. ... Adjectives: Neptunian Atmosphere Surface pressure: (?)â‰«(?) 100 kPa : is asked the pressure at the cloud level. ... A simulated view of Naiad orbiting Neptune with The Sun in the distance. ... A simulated view of Thalassa orbiting Neptune. ... A simulated view of Despina orbiting Neptune Despina (des-pee-na or des-pye-na; Latin DespÅ“na from Greek Î”ÎµÏƒÏ€Î¿Î¯Î½Î·) is the third known moon of Neptune. ... A simulated view of Galatea orbiting Neptune Galatea (gal-a-tee-a, Greek Î“Î±Î»Î±Ï„ÎµÎ¯Î±) is the fourth known moon of Neptune, named after Galatea, one of the Nereids of Greek legend. ... A simulated view of Larissa orbiting Neptune Larissa (la-ris-a, Greek Î›Î¬Ïá¿‘ÏƒÎ±) is the fifth of Neptunes known moons. ... Atmospheric pressure 0 kPa Proteus (proe-tee-us, Greek Î ÏÏ‰Ï„ÎÎ±Ï‚) is one of Neptunes moons. ... Triton (trye-tÉ™n, IPA: , Greek Î¤ÏÎ¯Ï„Ï‰Î½), or Neptune I, is the planet Neptunes largest moon. ... Nereid (IPA: , IPA: , Greek ÎÎ·ÏÎ·Î¯Î´Î±), or Neptune II, is a moon of Neptune. ... Halimede is a retrograde irregular satellite of Neptune. ... Sao is a prograde irregular satellite of Neptune. ... Laomedeia, or Neptune XII, is a prograde irregular satellite of Neptune. ... Psamathe (sam-a-thee, Greek Î¨Î±Î¼Î±Î¸ÎµÎ¹Î±, Latin PsamathÄ“) is an irregular natural satellite of Neptune. ... Neso, also known as Neptune XIII, is the outermost irregular natural satellite of Neptune. ... As of March 2007, there are five[1] known Neptune Trojans (named by analogy to the Trojan asteroids) which have the same orbital period as the planet. ... This is a list of the named rings and ring arcs of Neptune. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... 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. ... Apparent magnitude: up to -12. ... The relative sizes of and distance between Mars, Phobos, and Deimos, to scale. ... Some of Jupiters moons and their highly inclined orbits Jupiter has 63 known natural satellites. ... The Saturnian system (photographic montage) Saturn has fifty-six confirmed natural satellites, plus three unconfirmed moons. ... Uranus has 27 known moons. ... Image File history File links Download high resolution version (604x602, 23 KB)Cassini color image of Rhea taken Jan. ... The planet Pluto has three known moons. ... Dysnomia (officially designated (136199) Eris I Dysnomia) is a moon of the dwarf planet Eris. ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... This article or section does not adequately cite its references or sources. ... Titan (, from Ancient Greek Î¤á¿‘Ï„Î¬Î½) or Saturn VI is the largest moon of Saturn and the second largest moon in the solar system,[4] after Jupiters moon Ganymede. ... This article or section does not cite its references or sources. ... Atmospheric characteristics Atmospheric pressure trace Sulfur dioxide 90% Io (eye-oe, IPA: , Greek á¿™ÏŽ) is the innermost of the four Galilean moons of Jupiter. ... Apparent magnitude: up to -12. ... Apparent magnitude: 5. ... Triton (trye-tÉ™n, IPA: , Greek Î¤ÏÎ¯Ï„Ï‰Î½), or Neptune I, is the planet Neptunes largest moon. ... Atmospheric pressure Titania (ti-taan-ee-É™ or tye-tan-ee-É™) is the largest moon of Uranus. ... Atmosphere none Rhea (ree-a, Greek â€˜Î¡ÎÎ±) is the second largest moon of Saturn and was discovered in 1672 by Giovanni Domenico Cassini. ... Atmospheric pressure 0 kPa Oberon (oe-bur-on) is the outermost of the major moons of the planet Uranus. ... Iapetus (eye-ap-É™-tÉ™s, IPA , Greek Î™Î±Ï€ÎµÏ„ÏŒÏ‚) is the third-largest moon of Saturn, discovered by Giovanni Domenico Cassini in 1671. ... Charon (shair-É™n or kair-É™n (key), IPA , Greek Î§Î¬ÏÏ‰Î½), discovered in 1978, is, depending on the definition employed, either the largest moon of Pluto or one member of a double dwarf planet with Pluto being the other member. ... Atmospheric pressure 0 kPa Umbriel (um-bree-É™l, IPA ) is a moon of Uranus discovered on 1851-10-24 by William Lassell. ... Atmospheric pressure 0 kPa Ariel (air-ee-É™l, IPA ) is a moon of Uranus discovered on 24 October 1851 by William Lassell. ... Atmosphere none Dione (dye-oe-nee, Greek Î”Î¹ÏŽÎ½Î·) is a moon of Saturn discovered by Giovanni Cassini in 1684. ... Atmosphere none Tethys (tee-thÉ™s or teth-É™s, IPA , Greek Î¤Î·Î¸ÏÏ‚) is a moon of Saturn that was discovered by Giovanni Domenico Cassini in 1684. ... [5] Atmospheric characteristics Pressure trace, significant spatial variability [6], [7] Water vapour 91% [8] Carbon dioxide 3. ... Miranda (IPA: ) is the smallest and innermost of Uranus major moons. ... Atmospheric pressure 0 kPa Proteus (proe-tee-us, Greek Î ÏÏ‰Ï„ÎÎ±Ï‚) is one of Neptunes moons. ... Mimas (mee-mÉ™s or mye-mÉ™s, IPA: , Greek ÎœÎ¯Î¼á¾±Ï‚, rarely ÎœÎ¯Î¼Î±Î½Ï‚) is a moon of Saturn that was discovered in 1789 by William Herschel. ... In astronomy, an inner satellite is a natural satellite following a prograde, low inclination orbit inwards of the large satellites of the parent planet. ... A Trojan moon is a natural satellite of a planet occupying the L4 or L5 equilateral Lagrangian points of a primary-moon system. ... In astronomy, an irregular satellite is a natural satellite following a distant, inclined, often retrograde orbit and believed to be captured as opposed to a regular satellite, formed in situ. ... This is a list of natural satellites in the solar system: Mercury: none Venus: none Earth: Moon Mars: Phobos Deimos Jupiter: see Jupiters natural satellites Saturn: see Saturns natural satellites Uranus: see Uranus natural satellites Neptune: see Neptunes natural satellites Pluto: Charon In addition, various asteroids are... This is a list of natural satellites in the solar system, ordered from largest to smallest by average diameter. ... This timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. ... The naming of natural satellites has been the responsibility of the IAUs committee for Planetary System Nomenclature since 1973. ... 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. ... The Sun is the star at the center of the Solar System. ... This article is about the planet. ... Adjectives: Venusian or (rarely) Cytherean Atmosphere Surface pressure: 9. ... Adjectives: Terrestrial, Terran, Telluric, Tellurian, Earthly Atmosphere Surface pressure: 101. ... Adjectives: Martian Atmosphere Surface pressure: 0. ... Spectral type: G[8] Absolute magnitude: 3. ... Adjectives: Jovian Atmosphere Surface pressure: 20â€“200 kPa[4] (cloud layer) Composition: ~86% H2 ~13% Helium 0. ... Adjectives: Saturnian Atmosphere Surface pressure: 140 kPa Composition: >93% hydrogen >5% helium 0. ... Adjectives: Uranian Atmosphere Surface pressure: 120 kPa (at the cloud level) Composition: 83% Hydrogen 15% Helium 1. ... Adjectives: Neptunian Atmosphere Surface pressure: (?)â‰«(?) 100 kPa : is asked the pressure at the cloud level. ... Adjectives: Plutonian Atmosphere Surface pressure: 0. ... Absolute magnitude: âˆ’1. ... The eight planets and three dwarf planets of the Solar System. ... Artists impression of Pluto (background) and Charon (foreground). ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... Apparent magnitude: up to -12. ... The relative sizes of and distance between Mars, Phobos, and Deimos, to scale. ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... Some of Jupiters moons and their highly inclined orbits Jupiter has 63 known natural satellites. ... The Saturnian system (photographic montage) Saturn has fifty-six confirmed natural satellites, plus three unconfirmed moons. ... Uranus has 27 known moons. ... The planet Pluto has three known moons. ... Dysnomia (officially designated (136199) Eris I Dysnomia) is a moon of the dwarf planet Eris. ... A Small Solar System Body (SSSB) is a term defined in 2006 by the International Astronomical Union to describe objects in the Solar System that are neither planets nor dwarf planets: [1] This encompasses: all minor planets apart from the dwarf planets, : the classical asteroids, (except for 1 Ceres, the... It has been suggested that bolide be merged into this article or section. ... It has been suggested that minor planet be merged into this article or section. ... For details on the physical properties of bodies in the asteroid belt see Asteroid and Main-belt comet. ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... A trans-Neptunian object (TNO) is any object in the solar system that orbits the sun at a greater distance on average than Neptune. ... Artists rendering of the Kuiper Belt and hypothetical more distant Oort cloud. ... The scattered disc (or scattered disk) is a distant region of our solar system, thinly populated by icy planetoids known as scattered disk objects (SDOs), a subset of the broader family of trans-Neptunian objects (TNOs). ... Comet Hale-Bopp Comet McNaught as seen from Swifts Creek, Victoria, Australia on 23 January 2007 A comet is a small body in the solar system that orbits the Sun and (at least occasionally) exhibits a coma (or atmosphere) and/or a tail â€” both primarily from the effects of... This image is an artists rendering of the Oort cloud and the Kuiper Belt. ... See also Lists of astronomical objects Category: ... Below is a list of solar system objects with diameter >500km: The Sun, a spectral class G2 star Mercury Venus Earth Moon Mars Jupiter Io Europa Ganymede Callisto complete list of Jupiters natural satellites Saturn Tethys Dione Rhea Titan Iapetus complete list of Saturns natural satellites Uranus Ariel... This is a list of solar system objects by radius, arranged in descending order of mean volumetric radius. ... This is a list of Solar system objects by mass, in decreasing order. ...

Encyclopedia > Neptune's natural satellites

Contents