Original: 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.
Simplified: A-type asteroids are fairly uncommon closer 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.