A-type asteroids are relatively uncommon inner-belt
asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
...
s that have a strong, broad 1
μm olivine
The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...
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 February 2019, only 17 had been discovered:
See also
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Asteroid spectral types
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 differentiate ...
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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