Concept
Natural satellite
Related concepts (79)
Ray system
A ray system comprises radial streaks of fine ejecta thrown out during the formation of an impact crater, looking somewhat like many thin spokes coming from the hub of a wheel. The rays may extend for lengths up to several times the diameter of their originating crater, and are often accompanied by small secondary craters formed by larger chunks of ejecta. Ray systems have been identified on the Moon, Earth (Kamil Crater), Mercury, and some moons of the outer planets.
Planetary nomenclature
Planetary nomenclature, like terrestrial nomenclature, is a system of uniquely identifying features on the surface of a planet or natural satellite so that the features can be easily located, described, and discussed. Since the invention of the telescope, astronomers have given names to the surface features they have discerned, especially on the Moon and Mars. To found an authority on planetary nomenclature, the International Astronomical Union (IAU) was organized in 1919 to designate and standardize names for features on Solar System bodies.
Gravitational compression
Gravitational compression is a phenomenon in which gravity, acting on the mass of an object, compresses it, reducing its size and increasing the object's density. At the center of a planet or star, gravitational compression produces heat by the Kelvin–Helmholtz mechanism. This is the mechanism that explains how Jupiter continues to radiate heat produced by its gravitational compression. The most common reference to gravitational compression is stellar evolution.
Larissa (moon)
Larissa, also known as Neptune VII, is the fifth-closest inner satellite of Neptune. It is named after Larissa, a lover of Poseidon (Neptune) in Greek mythology and eponymous nymph of the city in Thessaly, Greece. It was first discovered by Harold J. Reitsema, William B. Hubbard, Larry A. Lebofsky and David J. Tholen, based on fortuitous ground-based stellar occultation observations on May 24, 1981, given the temporary designation S/1981 N 1 and announced on May 29, 1981.
Satellite system (astronomy)
A satellite system is a set of gravitationally bound objects in orbit around a planetary mass object (incl. sub-brown dwarfs and rogue planets) or minor planet, or its barycenter. Generally speaking, it is a set of natural satellites (moons), although such systems may also consist of bodies such as circumplanetary disks, ring systems, moonlets, minor-planet moons and artificial satellites any of which may themselves have satellite systems of their own (see Subsatellites).
Hiʻiaka (moon)
Hiiaka is the larger, outer moon of the trans-Neptunian dwarf planet Haumea. It is named after one of the daughters of Haumea, Hiiaka, the patron goddess of the Big Island of Hawaii. It orbits once every 49.12days at a distance of 49880km, with an eccentricity of 0.0513 and an inclination of 126.356°. Assuming its estimated diameter of over 300 km is accurate, it may be the fourth- or fifth-largest known moon of a Trans-Neptunian object, after Pluto I Charon, Eris I Dysnomia, Orcus I Vanth, and possibly Varda I Ilmarë and Salacia I Actaea.
Thalassa (moon)
Thalassa θəˈlæsə, also known as Neptune IV, is the second-innermost satellite of Neptune. Thalassa was named after sea goddess Thalassa, a daughter of Aether and Hemera from Greek mythology. "Thalassa" is also the Greek word for "sea". Thalassa was discovered sometime before mid-September 1989 from the images taken by the Voyager 2 probe. It was given the temporary designation S/1989 N 5. The discovery was announced (IAUC 4867) on 29 September 1989, and mentions "25 frames taken over 11 days", implying a discovery date of sometime before 18 September.
Iron–nickel alloy
An iron–nickel alloy or nickel–iron alloy, abbreviated FeNi or NiFe, is a group of alloys consisting primarily of the elements nickel (Ni) and iron (Fe). It is the main constituent of the "iron" planetary cores and iron meteorites. In chemistry, the acronym NiFe refers to an iron–nickel catalyst or component involved in various chemical reactions, or the reactions themselves; in geology, it refers to the main constituents of telluric planetary cores (including Earth's).
Cordelia (moon)
Cordelia is the innermost known moon of Uranus. It was discovered from the images taken by Voyager 2 on January 20, 1986, and was given the temporary designation S/1986 U 7. It was not detected again until the Hubble Space Telescope observed it in 1997. Cordelia takes its name from the youngest daughter of Lear in William Shakespeare's King Lear. It is also designated Uranus VI. Other than its orbit, radius of 20 km and geometric albedo of 0.08 virtually nothing is known about it.