11:30 AM - 11:45 AM
[PPS02-10] Investigation of hydrated minerals on the main belt asteroids from the AKARI near-infrared spectroscopy
Keywords:asteroids, hydrated minerals, near-infrared spectroscopy
The Japanese infrared astronomical satellite AKARI, launched in 2006, had the capability of spectroscopy in targeted observation mode. Low-resolution spectroscopic observations were performed using the near-infrared channel (2.5-5 micron) of the Infrared Camera (IRC) on board AKARI, which provide valuable data because of its high sensitivity and unique wavelength coverage. We carried out a spectroscopic survey of asteroids with the IRC. In the warm mission period of AKARI (called Phase 3), 147 pointed observations for 66 asteroids were performed in the grism mode of 2.5-5 micron band.
The observed objects comprise 23 C-types, 17 S-types, 22 X-types, 3 D-types, and 1 V-type. From these observations, most C-type asteroids (17/23) were found to show a clear absorption feature related to hydrated minerals at a peak wavelength of around 2.7 micron. On the other hand, no S-types (17) have any clear absorption in this wavelength region. Some X-types (3/22) and D-types (1/3) have absorption feature like C-types.
In this talk, we present the results of the near-infrared asteroid spectroscopic survey with AKARI, and discuss the distribution of hydrated and/or hydroxylated minerals on asteroids in the main belt region.