A-type asteroids are relatively uncommon inner-belt
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). As ...
s that have a strong, broad 1
μm
The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...
olivine
The mineral olivine () is a magnesium iron Silicate minerals, silicate with the chemical formula . It is a type of Nesosilicates, nesosilicate or orthosilicate. The primary component of the Earth's upper mantle (Earth), upper mantle, it is a com ...
feature and a very reddish spectrum shortwards of 0.7 μm. They are thought to come from the completely differentiated
mantle of an asteroid, and appear to have a high density. One survey found that 7 similar A-,
V- and
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
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 ...
References
External links
Mineralogic and Temperature-Induced Spectral Investigations of A-type Asteroids: (246) Asporina and (446) Aeternitas V. Reddy, Lunar and Planetary Science XXXVI (2005)
Asteroid spectral classes
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