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L-type Asteroid
L-type asteroids are relatively uncommon asteroids with a strongly reddish spectrum shortwards of 0.75 μm, and a featureless flat spectrum longwards of this. In comparison with the K-type, they exhibit a more reddish spectrum at visible wavelengths and a flat spectrum in the infrared. These asteroids were described as "featureless" S-types in the Tholen classification. The L-type was formally introduced in the SMASS classification, although previous studies had noted the unusual spectra of two of its members 387 Aquitania and 980 Anacostia. There are 41 asteroids classified as L-types in the SMASS taxonomy. Ld-type asteroids The Ld type is a grouping proposed in the SMASS classification for asteroids with an L-like flat spectrum longwards of 0.75 μm, but even redder in visible wavelengths, like the D-type. An example may be 728 Leonisis, although it has also been classified as an A-type. References See also * Asteroid spectral types An asteroid spectral ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). Asteroids are rocky, metallic, or icy bodies with no atmosphere, and are broadly classified into C-type asteroid, C-type (carbonaceous), M-type asteroid, M-type (metallic), or S-type asteroid, S-type (silicaceous). The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across to Ceres (dwarf planet), Ceres, a dwarf planet almost 1000 km in diameter. A body is classified as a comet, not an asteroid, if it shows a coma (tail) when warmed by solar radiation, although recent observations suggest a continuum between these types of bodies. Of the roughly one million known asteroids, the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 astronomical unit, AU ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K-type Asteroid
K-type asteroids are relatively uncommon asteroids with a moderately reddish spectrum shortwards of 0.75 μm, and a slight bluish trend longwards of this. They have a low albedo. Their spectrum resembles that of CV and CO meteorites. A larger K type is 9 Metis. These asteroids were described as "featureless" S-types in the Tholen classification. The K-type was proposed by J. F. Bell and colleagues in 1988 for bodies having a particularly shallow 1 μm absorption feature, and lacking the 2 μm absorption. These were found during studies of the Eos family of asteroids. See also *Asteroid spectral types An asteroid spectral type is assigned to asteroids based on their reflectance spectrum, color, and sometimes Astronomical albedo, albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not p ... * L-type asteroid * S-type asteroid * X-type asteroid * 181 Eucharis * 221 Eos * 402 Chloë * 417 Suevia ReferencesJ. F. Bell ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-type Asteroid
S-type (stony-type or silicaceous-type) asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are of this type, making it the second-most common after the carbonaceous C-type. Characteristics S-type asteroids, with an astronomical albedo of typically 0.20, are moderately bright and consist mainly of iron- and magnesium-silicates. They are dominant in the inner part of the asteroid belt within 2.2 AU, common in the central belt within about 3 AU, but become rare farther out. The largest are 3 Juno (about 240–250 km across) and 15 Eunomia (230 km), with other large S-types being 29 Amphitrite, 532 Herculina and 7 Iris. These largest S-types are visible in 10x50 binoculars at most oppositions; the brightest, 7 Iris, can occasionally become brighter than +7.0, which is a higher magnitude than any asteroid except ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid Spectral Types
An asteroid spectral type is assigned to asteroids based on their reflectance spectrum, color, and sometimes Astronomical albedo, albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not planetary differentiation, internally differentiated, the surface and internal compositions are presumably similar, while large bodies such as Ceres (dwarf planet), Ceres and 4 Vesta, Vesta are known to have internal structure. Over the years, there has been a number of surveys that resulted in a set of different taxonomic systems such as the Tholen classification, Tholen, SMASS classification, SMASS and #Bus–DeMeo classification, Bus–DeMeo classifications. Taxonomic systems In 1975, astronomers Clark R. Chapman, David Morrison (astrophysicist), David Morrison, and Ben Zellner developed a simple taxonomic system for asteroids based on color, albedo, and spectral line, spectral shape. The three categories were labelled "C-type asteroi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
387 Aquitania
387 Aquitainia, provisional designation , is a Postremian asteroid from the central regions of the asteroid belt, approximately 101 kilometers in diameter. Discovered by Fernand Courty at the Bordeaux Observatory in 1894, it was named for the French region of Aquitaine, the former province of Gallia Aquitania in the ancient Roman Empire. Discovery ''Aquitania'' was discovered by French astronomer Fernand Courty at the Bordeaux Observatory on 5 March 1894. It was second of his two asteroid discoveries. The first was 384 Burdigala. Classification and orbit ''Aquitania'' is the largest member of the Postrema family (), a mid-sized central asteroid family of little more than 100 members. It orbits the Sun in the central main-belt at a distance of 2.1–3.4 AU once every 4 years and 6 months (1,657 days). Its orbit has an eccentricity of 0.24 and an inclination of 18 ° with respect to the ecliptic. Physical characteristics In the Tholen and SMASS classification, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
980 Anacostia
980 Anacostia is a minor planet orbiting the Sun that was discovered by American astronomer George Henry Peters on 21 November 1921. The name recognizes the Anacostia River and an historic neighborhood of the same name in the city of Washington, D.C. Measurements using the adaptive optics system at the W. M. Keck Observatory give a diameter of 70 ± 6 km. This is 23% smaller than the diameter estimated from the IRAS observatory data. The size ratio between the major and minor axes is 1.09. Polarimetric study of this asteroid reveals anomalous properties that suggests the regolith consists of a mixture of low and high albedo material. This may have been caused by fragmentation of an asteroid substrate with the spectral properties of CO3/CV3 carbonaceous chondrites Carbonaceous chondrites or C chondrites are a class of chondritic meteorites comprising at least 8 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. The C chon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D-type Asteroid
D-type asteroids have a very low albedo and a featureless reddish spectrum. It has been suggested that they have a composition of organic-rich silicates, carbon and anhydrous silicates, possibly with water ice in their interiors. D-type asteroids are found in the outer asteroid belt The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ... and beyond; examples are 152 Atala, 944 Hidalgo and most Jupiter trojans. It has been suggested that the Tagish Lake meteorite was a fragment from a D-type asteroid, and that the Martian moon Phobos is closely related. The Nice model suggests that D-type asteroids may have originated in the Kuiper belt. 46 D-type asteroids are known, including: 3552 Don Quixote, 944 Hidalgo, 624 Hektor, and 10199 Chariklo. Examples A list of some of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
728 Leonisis
728 Leonisis is an asteroid of the Flora family, discovered by Austrian astronomer Johann Palisa on 16 February 1912 from Vienna. There is some uncertainty as to its spectral class. It has been previously placed in the rare A and Ld classes. These are generally "stony" spectra, but with significant deviations from the usual S-type. The unusual spectrum brings Leonisis' membership in the Flora family into doubt. Photometric observations of this asteroid from the Organ Mesa Observatory in Las Cruces, New Mexico, during 2010 gave a light curve In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis ... with a period of 5.5783 ± 0.0002 hours and a brightness variation of 0.20 ± 0.04 magnitude. References External links * * Flora asteroids Leonisis 19120216 Leonisis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A-type Asteroid
A-type asteroids are relatively uncommon inner-belt asteroids that have a strong, broad 1 micrometre, μm olivine feature and a very reddish spectrum shortwards of 0.7 μm. They are thought to come from the completely differentiated Mantle (geology), mantle of an asteroid, and appear to have a high density. One survey found that 7 similar A-, V-type asteroid, V- and X-type asteroid, X-type asteroids had an average density of .P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. ''Astronomy & Astrophysics'' 54, A56 List A-type asteroids are so rare that as of August 2024, only 17 had been discovered: See also *Asteroid spectral types References External links Mineralogic and Temperature-Induced Spectral Investigations of A-type Asteroids: (246) Asporina and (446) Aeternitas Vishnu Vardhan Reddy, V. Reddy, Lunar and Planetary Science XXXVI (2005) Asteroid spectral classes A-type asteroids, {{belt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JPL Solar System Dynamics
The Jet Propulsion Laboratory (JPL) is a Federally funded research and development centers, federally funded research and development center (FFRDC) in La Cañada Flintridge, California, Crescenta Valley, United States. Founded in 1936 by California Institute of Technology (Caltech) researchers, the laboratory is now owned and sponsored by NASA and administered and managed by Caltech. The primary function of the laboratory is the construction and operation of planetary robotic spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating the NASA Deep Space Network (DSN). Among the major active projects at the laboratory, some are the Mars 2020 mission, which includes the ''Perseverance (rover), Perseverance'' rover; the Mars Science Laboratory mission, including the ''Curiosity (rover), Curiosity'' rover; the ''Mars Reconnaissance Orbiter''; the ''Juno (spacecraft), Juno'' spacecraft orbiting Jupiter; the ''Soil Moisture Active P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid Spectral Types
An asteroid spectral type is assigned to asteroids based on their reflectance spectrum, color, and sometimes Astronomical albedo, albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not planetary differentiation, internally differentiated, the surface and internal compositions are presumably similar, while large bodies such as Ceres (dwarf planet), Ceres and 4 Vesta, Vesta are known to have internal structure. Over the years, there has been a number of surveys that resulted in a set of different taxonomic systems such as the Tholen classification, Tholen, SMASS classification, SMASS and #Bus–DeMeo classification, Bus–DeMeo classifications. Taxonomic systems In 1975, astronomers Clark R. Chapman, David Morrison (astrophysicist), David Morrison, and Ben Zellner developed a simple taxonomic system for asteroids based on color, albedo, and spectral line, spectral shape. The three categories were labelled "C-type asteroi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid Spectral Classes
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the inner Solar System or is co-orbital with Jupiter (Trojan asteroids). Asteroids are rocky, metallic, or icy bodies with no atmosphere, and are broadly classified into C-type (carbonaceous), M-type (metallic), or S-type (silicaceous). The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across to Ceres, a dwarf planet almost 1000 km in diameter. A body is classified as a comet, not an asteroid, if it shows a coma (tail) when warmed by solar radiation, although recent observations suggest a continuum between these types of bodies. Of the roughly one million known asteroids, the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 AU from the Sun, in a region known as the main asteroid belt. The total mass of all the asteroids combined is only 3% that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
