The nature of c-class asteroids from 3-μm spectrophotometry
Abstract
We present narrowband spectrophotometry between 2.3 and 3.5 μm for 14 main-belt C asteroids greater than 100 km in diameter. Absorption features at 3 μm due to water of hydration are present in the spectra of 9 of the asteroids, with intensities ranging from 6 to 23%. The other 5 asteroids have no 3-μm absorption greater than 2% in intensity. The strength of the "water" feature in the spectra correlates positively with the strength of the UV absorption feature shortward of 0.4 μm, and negatively with the slope of the continuum between 1.2 and 2.2 μm. These correlations are the same as those seen in laboratory spectra of carbonaceous chondrites, whose silicate compositions range from hydrated phyllosilicates to anhydrous olivine. We find no correlation between composition and semimajor axis for C asteroids as a class. The present C-asteroid population may be fragments of larger parent bodies with anhydrous C3-like cores and hydrated C11- or C2M-like mantles.
- Publication:
-
Icarus
- Pub Date:
- August 1985
- DOI:
- 10.1016/0019-1035(85)90002-8
- Bibcode:
- 1985Icar...63..183F
- Keywords:
-
- Asteroids;
- Astronomical Photometry;
- Infrared Photometry;
- Narrowband;
- Spectrophotometry;
- Absorption Spectra;
- Broadband;
- Carbonaceous Chondrites;
- Chemical Composition;
- Ultraviolet Spectra;
- Water;
- ASTEROIDS;
- C ASTEROIDS;
- SPECTROPHOTOMETRY;
- CATALOG;
- SIZE;
- DIAMETER;
- ABSORPTION;
- FEATURES;
- HYDRATION;
- SPECTRA;
- INTENSITY;
- COMPARISONS;
- WATER;
- ULTRAVIOLET;
- WAVELENGTHS;
- LABORATORY STUDIES;
- METEORITES;
- CARBONACEOUS CHONDRITES;
- SILICATE;
- COMPOSITION;
- PARENT BODIES