Q-type asteroid

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Q-type asteroids are relatively uncommon inner-belt asteroids with a strong, broad 1 micrometre olivine and pyroxene feature, and a spectral slope that indicates the presence of metal. There are absorption features shortwards and longwards of 0.7 µm, and the spectrum is generally intermediate between the V and S-type.

Asteroid belt the circumstellar disk (accumulation of matter) in an orbit between those of Mars and Jupiter

The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets. The asteroid belt is also termed the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids. About half the mass of the belt is contained in the four largest asteroids: Ceres, Vesta, Pallas, and Hygiea. The total mass of the asteroid belt is approximately 4% that of the Moon, or 22% that of Pluto, and roughly twice that of Pluto's moon Charon.

Micrometre one millionth of a metre

The micrometre or micrometer, also commonly known by the previous name micron, is an SI derived unit of length equalling 1×10−6 metre ; that is, one millionth of a metre.

Olivine Magnesium iron silicate solid solution series mineral

The mineral olivine is a magnesium iron silicate with the formula (Mg2+, Fe2+)2SiO4. Thus it is a type of nesosilicate or orthosilicate. It is a common mineral in Earth's subsurface but weathers quickly on the surface.

Q-type asteroids are spectrally more similar to ordinary chondrite meteorites (types H, L, LL) than any other asteroid type. This has led scientists to speculate that they are abundant, but only about 20 of this type has been characterized. [1] Examples of Q-type asteroids are: 1862 Apollo, 2102 Tantalus, 3753 Cruithne, 6489 Golevka, and 9969 Braille.

Ordinary chondrite

The ordinary chondrites are a class of stony chondritic meteorites. They are by far the most numerous group and comprise about 87% of all finds. Hence, they have been dubbed "ordinary". The ordinary chondrites are thought to have originated from three parent asteroids, with the fragments making up the H chondrite, L chondrite and LL chondrite groups respectively.

H chondrite

The H type ordinary chondrites are the most common type of meteorite, accounting for approximately 40% of all those catalogued, 46% of the ordinary chondrites, and 44% of the chondrites. The ordinary chondrites are thought to have originated from three parent asteroids, whose fragments make up the H chondrite, L chondrite and LL chondrite groups respectively.

L chondrite

The L type ordinary chondrites are the second most common group of meteorites, accounting for approximately 35% of all those catalogued, and 40% of the ordinary chondrites. The ordinary chondrites are thought to have originated from three parent asteroids, with the fragments making up the H chondrite, L chondrite and LL chondrite groups respectively.

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S-type asteroid asteroid spectral type

S-type asteroids are asteroids with a spectral type that is indicative of a siliceous mineralogical composition, hence the name. Approximately 17% of asteroids are of this type, making it the second most common after the carbonaceous C-type.

Aten asteroid group of near-Earth asteroids

The Aten asteroids are a dynamical group of asteroids whose orbits bring them into proximity with Earth. By definition, Atens are Earth-crossing asteroids (a < 1.0 AU and Q > 0.983 AU). The group is named after 2062 Aten, the first of its kind, discovered on 7 January 1976 by American astronomer Eleanor Helin at Palomar Observatory. As of 2019, 1490 Atens have been discovered, of which 12 are named. Many Atens are classified as potentially hazardous asteroids.

A-type asteroids are relatively uncommon inner-belt asteroids that have a strong, broad 1 µm olivine feature and a very reddish spectrum shortwards of 0.7 µm. They are thought to come from the completely differentiated mantle of an asteroid.

R-type asteroids are moderately bright, relatively uncommon inner-belt asteroids that are spectrally intermediate between the V and A-type asteroids. The spectrum shows distinct olivine and pyroxene features at 1 and 2 micrometres, with a possibility of plagioclase. Shortwards of 0.7 μm the spectrum is very reddish.

P-type asteroids have 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 interior. P-type asteroids are found in the outer asteroid belt and beyond. There are 33 known P-type asteroids.

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 and beyond; examples are 152 Atala, and 944 Hidalgo as well as the majority of 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.

B-type asteroid uncommon type of carbonaceous asteroid

B-type asteroids are a relatively uncommon type of carbonaceous asteroid, falling into the wider C-group. In the asteroid population, B-class objects can be found in the outer asteroid belt, and also dominate the high-inclination Pallas family which includes the second-largest asteroid 2 Pallas. They are thought to be primitive, volatile-rich remnants from the early Solar System. There are 65 known B-type asteroids in the SMASS classification, and 9 in the Tholen classification as of March 2015.

68 Leto main-belt asteroid

Leto is a large main belt asteroid. Its spectral type is S. It was discovered by Robert Luther on April 29, 1861. The asteroid is named after Leto, the mother of Apollo and Artemis in Greek mythology.

77 Frigga main-belt asteroid

Frigga is a large, M-type, possibly metallic main-belt asteroid. It was discovered by C. H. F. Peters on November 12, 1862. It is named after Frigg, the Norse goddess.

201 Penelope main-belt asteroid

Penelope is a large main belt asteroid that was discovered by Austrian astronomer Johann Palisa on August 7, 1879, in Pola. The asteroid is named after Penelope, the wife of Odysseus in Homer's The Odyssey.

Oppavia is a sizeable Main belt asteroid. It classified as a dark P-type asteroid.

Heidelberga is a large Main belt asteroid that was discovered by German astronomer Max Wolf on 4 March 1892 in Heidelberg.

Janina is a Themistian asteroid, approximately 46 kilometers in diameter. It is spectral B-type and is probably composed of primitive carbonaceous chondritic material.

Vienna is a typical Main belt asteroid. The Tholen spectral type is S and the SMASSII spectral type is K.

Berolina is a typical Main belt asteroid.

Nephele is a large Themistian asteroid. It is spectral C-type and is probably composed of carbonaceous material.

An asteroid spectral type is assigned to asteroids based on their emission spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally differentiated, the surface and internal compositions are presumably similar, while large bodies such as Ceres and 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, SMASS and Bus–DeMeo classification.

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.

2311 El Leoncito, provisional designation 1974 TA1, is a dark and reddish asteroid from the outer region of the asteroid belt, approximately 53 kilometers in diameter. The asteroid was discovered by astronomers at Félix Aguilar Observatory at the Leoncito Astronomical Complex in Argentina on 10 October 1974. It was later named after the discovering site.

<span class="nowrap">(277475) 2005 WK<sub>4</sub></span> asteroid

(277475) 2005 WK4, provisional designation 2005 WK4, is a stony, sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group that passed Earth within 8.2 lunar distances on 8 August 2013. It was discovered on 27 November 2005, by astronomers of the Siding Spring Survey at Siding Spring Observatory, Australia.

References

  1. ↑ "JPL Small-Body Database Search Engine: spec. type = Q (SMASSII)". JPL Solar System Dynamics. Retrieved 2015-06-16.


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