THE NATURE OF LOW-ALBEDO ASTEROIDS FROM 3-MU-M MULTI-COLOR PHOTOMETRY

We present broadband and narrowband spectrometry (1.2 to 3.5 μm) of 16 low-albedo asteroids. This is an extension of our origin observations of the C-class asteroids (Feierberg et al. 1985) and now includes F-, P-, D-, and T-class asteroids. Although it has been thought previously that these outer belt and Trojan asteroids are more"primitive" than the Cs and thus should show a larger volatile content (i.e., hydrated silicates and organics), we find that most of them do not show the spectral signature of hydrated silicates. © 1990.