Follow-up observations for the Asteroid Catalog using AKARI Spectroscopic Observations

Abstract

In the 1-2.5 μm range, spectroscopic observations are made on the AcuA-spec asteroids, the spectra of which were obtained in a continuous covered mode between 2.5-5.0 μm by AKARI. Based on the Bus-DeMeo taxonomy (DeMeo et al. 2009, Icarus, 202, 160), all the AcuA-spec asteroids are classified, using both published and our observational data. Additionally, taking advantage of the Bus-DeMeo taxonomy characteristics, we constrain the characteristic of each spectral type by combining the taxonomy results with the other physical observational data from colorimetry, polarimetry, radar, and radiometry. As a result, it is suggested that certain C-, Cb-, B-type, dark X-, and D-complex asteroids have spectral properties compatible with those of anhydrous interplanetary dust particles with tiny bright material, such as water ice. This supports the proposal regarding the C-complex asteroids (Vernazza et al. 2015, ApJ, 806, 204; 2017, AJ, 153, 72). A combination of the Bus-DeMeo taxonomy for AcuA-spec asteroids with other physical clues, such as the polarimetric inversion angle, radar albedo, and mid-infrared spectroscopic spectra, will be beneficial for surface material constraints from the AcuA-spec asteroid observations.