L-type asteroids are relatively uncommon

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 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 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 differentiat ...

, although previous studies had noted the unusual spectra of two of its members

387 Aquitania Aquitania (minor planet designation: 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 Obser ...

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.

Ld-type asteroids

References

See also