The adjectival forms of the names of astronomical bodies are not always easily predictable. Attested adjectival forms of the larger bodies are listed below, along with the two small Martian moons; in some cases they are accompanied by their demonymic equivalents, which denote hypothetical inhabitants of these bodies.
For Classical (Greco-Roman) names, the adjectival and demonym forms normally derive from the oblique stem, which may differ from the nominative form used in English for the noun form. For instance, for a large portion of names ending in -s, the oblique stem and therefore the English adjective changes the -s to a -d, -t, or -r, as in Mars–Martian, Pallas–Palladian and Ceres–Cererian; [note 1] occasionally an -n has been lost historically from the nominative form, and reappears in the oblique and therefore in the English adjective, as in Pluto–Plutonian and Atlas–Atlantean.
Many of the more recent or more obscure names are only attested in mythological or literary contexts, rather than in specifically astronomical contexts. Forms ending in -ish or -ine, such as "Puckish", are not included below if a derivation in -an is also attested. Rare forms, or forms only attested with spellings not in keeping with the IAU-approved spelling (such as c for k), are shown in italics.
The suffix -ian is always unstressed: that is, /iən/ . The related ending -ean, from an e in the root plus a suffix -an, has traditionally been stressed (that is, /ˈiːən/ ) if the e is long ē in Latin (or is from ⟨η⟩ē in Greek); but if the e is short in Latin, the suffix is pronounced the same as -ian. In practice forms ending in -ean may be pronounced as if they were spelled -ian even if the e is long in Latin. This dichotomy should be familiar from the dual pronunciations of Caribbean as /ˌkærɪˈbiːən/ KARR-ə-BEE-ən and /kəˈrɪbiən/ kə-RIB-i-ən.
Name | Adjective | Demonym |
---|---|---|
asteroid | asteroidal, asteroidic | Asterite |
comet | cometary | |
cosmos, universe | cosmic, cosmian, universal | |
ecliptic | ecliptical, zodiacal | |
galaxy | galactic, galactian | |
meteoroid | meteoroidal | |
nebula | nebular | |
planet | planetary, planetic | |
planetoid | planetoidal | |
quasar | quasaric, quasarian | |
sky | celestial | |
star | astral, sidereal, siderean, stellar | |
supernova | supernovan |
Derivative forms of constellations are used primarily for meteor showers. The genitive forms of the constellations are used to name stars. (See List of constellations.) Other adjectival forms are less common.
Name | Adjective | Derivative |
---|---|---|
Andromeda | Andromedan | Andromedid |
Aquarius | Aquarian | Aquariid |
Aries | Arian | Arietid |
Auriga | Aurigal | Aurigid |
Bootes | Bootid | |
Cancer | Cancerian | Cancrid |
Carina | Carinal | Carinid |
Capricorn | Capricornian | Capricornid |
Centaurus | Centaurean, Centaurian | Centaurid |
Cetus | Cetid | |
Coma Berenices | Comal | Coma Berenicid |
Corona Austrina | Coronal | Corona Austrinid |
Crux | Crucial | Crucid |
Cygnus | Cygnean | Cygnid |
Dorado | Doradid | |
Draco | Draconic | Draconid |
Eridanus | Eridanid | |
Gemini | Geminian | Geminid |
Hydra, Hydrus | Hydrid | |
Leo | Leonic, Leonian, Leonean | Leonid |
Leo Minor | Leo Minorid | |
Libra | Libran | Librid |
Lyra | Lyrid | |
Monoceros | Monocerotid | |
Norma | Normid | |
Ophiuchus | Ophiuchid | |
Orion | Orionid | |
Pavo | Pavonid | |
Pegasus | Pegasean, Pegasarian | Pegasid |
Perseus | Perseid | |
Phoenix | Phoenicean | Phoenicid |
Pisces | Piscean, Piscian | Piscid |
Piscis Austrinus | Piscis Austrinid | |
Puppis | Puppid | |
Sagittarius | Sagittarian | Sagittariid |
Scorpius | Scorpian, Scorpionic | Scorpiid |
Taurus | Taurean, Taurian | Taurid |
Ursa Major, Ursa Minor | Ursal | Ursid |
Vela | Velar, Velic | Velid |
Virgo | Virginal, Virginian | Virginid |
zodiac | zodiacal |
Name | Adjective | Demonym |
---|---|---|
Sun, Sol, Helios | Solar, Heliacal, Phoebean, Phebean | Solarian |
Name | Adjective | Demonym |
---|---|---|
Ceres | Cererian, [1] Cererean [2] | Cererian |
Earth, Terra, Tellus, Gaia, Gaea | earthly, Terran, Terrestrial, Terrene, Tellurian, [3] Telluric, Gaian, Gaean | Earthling, Terran, Terrestrial, Tellurian, Earthian, Earther, Earthican |
Eris | Eridian [4] | |
Haumea | Haumean [5] | |
Jupiter | Jovian, Jupiterian, Zeusian | Jovian |
Makemake | Makemakean [6] | |
Mars | Martian, Martial, Arean [7] | Martian |
Mercury; Hermes (in the evening), Apollo (in the morning) | Mercurian, Mercurial, Hermean/Hermeian, Cyllenian, [8] Cyllenean | Mercurian, Hermean |
Neptune | Neptunian, Neptunial, Poseidean [9] | Neptunian |
Orcus | Orcean, [10] Orcan | |
Pallas | Palladian [11] | |
Pluto | Plutonic, Plutonian | Plutonian [11] |
Saturn | Saturnian, Saturnine, Cronian, [9] Kronian, [12] Saturnial [13] | Saturnian |
Sedna | Sednian [14] | |
Uranus | Uranian, Caelian | Uranian |
Vesta | Vestian, [15] [16] Vestan, [17] [18] Vestalian | Vestan, Vestian |
Venus; Hesperus , Vesper (in the evening), Eosphorus, Phosphorus, Phosphor (in the morning), Lucifer (in the day) | Venerian, Venusian, Cytherean, [19] Cytherian, [20] Hesperian, [21] Luciferian, [22] Phosphorian, [23] Aphroditan [24] | Venusian, Cytherean |
Name | Adjective | Demonym |
---|---|---|
Moon (Luna, Selene) | Lunar, Selenian, Cynthian | Lunarian, Selenite |
Deimos | Deimian [25] | |
Phobos | Phobian [26] |
Name | Adjective, demonym |
---|---|
Callisto | Callistoan, [27] Callistonian [28] |
Europa | Europan [29] |
Ganymede | Ganymedean, [30] Ganymedian |
Io | Ionian [31] |
Name | Adjective, demonym |
---|---|
Dione | Dionean [32] [33] |
Enceladus | Enceladean, [34] [35] Enceladan [36] [37] |
Hyperion | Hyperionian [38] |
Iapetus | Iapetian, [39] Japetian [11] |
Mimas | Mimantean, [35] Mimantian, [40] |
Rhea | Rhean [41] [42] |
Tethys | Tethyan [11] [43] [44] |
Titan | Titanian /taɪˈteɪniən/ , [45] [46] Titanean [47] |
Name | Adjective, demonym |
---|---|
Ariel | Arielian [48] |
Miranda | Mirandan, [49] Mirandian [50] |
Oberon | Oberonian [51] |
Titania | Titanian /tɪˈtɑːniən/ [52] |
Umbriel | Umbrielian [52] |
Name | Adjective, demonym |
---|---|
Triton | Tritonian [53] |
Charon | Charonian [54] |
Dysnomia | Dysnomian |
Name | Adjective |
---|---|
Milky Way Galaxy | Galactic, [55] Lacteal [56] |
Andromeda Galaxy | Andromedan |
Magellanic Clouds | Magellanic |
The ecliptic or ecliptic plane is the orbital plane of 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 against the background of stars. The ecliptic is an important reference plane and is the basis of the ecliptic coordinate system.
Jet Propulsion Laboratory (JPL) is a federally funded research and development center in Pasadena, California, United States. Founded in 1936 by Caltech researchers, the laboratory is now owned and sponsored by the National Aeronautics and Space Administration (NASA) and administered and managed by the California Institute of Technology.
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.
Vesta is one of the largest objects in the asteroid belt, with a mean diameter of 525 kilometres (326 mi). It was discovered by the German astronomer Heinrich Wilhelm Matthias Olbers on 29 March 1807 and is named after Vesta, the virgin goddess of home and hearth from Roman mythology.
Pallas is the second asteroid to have been discovered, after Ceres. Like Ceres, it is believed to have a mineral composition similar to carbonaceous chondrite meteorites, though significantly less hydrated than Ceres. It is the third-largest asteroid in the Solar System by both volume and mass, and is a likely remnant protoplanet. It is 79% the mass of Vesta and 22% the mass of Ceres, constituting an estimated 7% of the mass of the asteroid belt. Its estimated volume is equivalent to a sphere 507 to 515 kilometers in diameter, 90–95% the volume of Vesta.
A terrestrial planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, Venus, Earth and Mars. Among astronomers who use the geophysical definition of a planet, two or three planetary-mass satellites – Earth's Moon, Io, and sometimes Europa – may also be considered terrestrial planets. The large rocky asteroids Pallas and Vesta are sometimes included as well, albeit rarely. The terms "terrestrial planet" and "telluric planet" are derived from Latin words for Earth, as these planets are, in terms of structure, Earth-like. Terrestrial planets are generally studied by geologists, astronomers, and geophysicists.
Tethys, or Saturn III, is a fifth largest moon of Saturn about 1,060 km (660 mi) across. It was discovered by G. D. Cassini in 1684 and is named after the titan Tethys of Greek mythology.
Janus is an inner satellite of Saturn. It is also known as Saturn X. It is named after the mythological Janus.
Hyperion, also known as Saturn VII, is a moon of Saturn distinguished by its highly irregular shape, chaotic rotation, extremely low density and its unexplained sponge-like appearance. It was the first non-round moon to be discovered.
Mimas, also designated Saturn I, is a natural satellite of Saturn. With a mean diameter of 396.4 kilometres or 246.3 miles, Mimas is the smallest astronomical body known to be roughly rounded in shape due to its own gravity. Mimas's low density, 1.15 g/cm3, indicates that it is composed mostly of water ice with only a small amount of rock, and study of Mimas's motion confirmed that it has a liquid ocean beneath its surface ice. The surface of Mimas is heavily cratered and shows little signs of recent geological activity. A notable feature of Mimas' surface is Herschel, one of the largest craters relative to the size of the parent body in the Solar System. Herschel measures 139 kilometres across, about one-third of Mimas's mean diameter, and is believed to be formed from an extremely energetic impact event. The crater's name is derived from the discoverer of Mimas, William Herschel, in 1789. The moon's presence has created one of the largest 'gaps' in Saturn's ring, named the Cassini Division, due to orbital resonance destabilizing the particles' orbit there.
Though no standard exists, numerous calendars and other timekeeping approaches have been proposed for the planet Mars. The most commonly seen in the scientific literature denotes the time of year as the number of degrees on its orbit from the northward equinox, and increasingly there is use of numbering the Martian years beginning at the equinox that occurred April 11, 1955.
Many astronomical phenomena viewed from the planet Mars are the same as or similar to those seen from Earth; but some are quite different. For example, because the atmosphere of Mars does not contain an ozone layer, it is also possible to make UV observations from the surface of Mars.
Cydonia is a region on the planet Mars that has attracted both scientific and popular interest. The name originally referred to the albedo feature that was visible from earthbound telescopes. The area borders the plains of Acidalia Planitia and the highlands of Arabia Terra. The region includes the named features Cydonia Mensae, an area of flat-topped mesa-like features; Cydonia Colles, a region of small hills or knobs; and Cydonia Labyrinthus, a complex of intersecting valleys. As with other albedo features on Mars, the name Cydonia was drawn from classical antiquity, in this case from Kydonia, a historic polis on the island of Crete. Cydonia contains the "Face on Mars", located about halfway between the craters Arandas and Bamberg.
Schiaparelli is an impact crater on Mars, located near the planet's equator at latitude 3° south and longitude 344° in the Sinus Sabaeus quadrangle. It measures approximately 459 kilometers (285-miles) in diameter and was named after Italian astronomer Giovanni Schiaparelli, known for his observations of the Red Planet and his mistranslated term "canali". The name was adopted by IAU's Working Group for Planetary System Nomenclature in 1973.
In planetary nomenclature, a tholus is a small domical mountain or hill. The word is from the Greek θόλος, tholos, which means a circular building with a conical or vaulted roof. The Romans transliterated the word into the Latin tholus, which means cupola or dome. In 1973, the International Astronomical Union (IAU) adopted tholus as one of a number of official descriptor terms for topographic features on Mars and other planets and satellites. One justification for using neutral Latin or Greek descriptors was that it allowed features to be named and described before their geology or geomorphology could be determined. For example, many tholi appear to be volcanic in origin, but the term does not imply a specific geologic origin. Currently, the IAU recognizes 56 descriptor terms. Tholi are present on Venus, Mars, asteroid 4 Vesta, dwarf planet Ceres, and on Jupiter's moon Io.
Endeavour is an impact crater located in the Meridiani Planum extraterrestrial plain within the Margaritifer Sinus quadrangle (MC-19) region of the planet Mars. Endeavour is about 22 kilometers (14 mi) in diameter. Using Mars Reconnaissance Orbiter data, phyllosilicate-bearing outcrops have been detected along its rim. These minerals may have formed under wet conditions in a low-acidic environment during the early history of Mars. There are raised rim segments to the north, east, and southwest. The rim has become worn, rounded and degraded, with infilling of plains material in a manner similar to the Victoria crater.
Interplanetary contamination refers to biological contamination of a planetary body by a space probe or spacecraft, either deliberate or unintentional.
A planetary surface is where the solid or liquid material of certain types of astronomical objects contacts the atmosphere or outer space. Planetary surfaces are found on solid objects of planetary mass, including terrestrial planets, dwarf planets, natural satellites, planetesimals and many other small Solar System bodies (SSSBs). The study of planetary surfaces is a field of planetary geology known as surface geology, but also a focus on a number of fields including planetary cartography, topography, geomorphology, atmospheric sciences, and astronomy. Land is the term given to non-liquid planetary surfaces. The term landing is used to describe the collision of an object with a planetary surface and is usually at a velocity in which the object can remain intact and remain attached.
Bethany List Ehlmann is an American geologist and a professor of Planetary Science at California Institute of Technology. A leading researcher in planetary geology, Ehlmann is also the President of The Planetary Society, Director of the Keck Institute for Space Studies, and a Research Scientist at NASA's Jet Propulsion Laboratory.
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