1 research outputs found
Surface physical condition of asteroid Ryugu using close-up optical and thermal images
In 2018, the Hayabusa2 spacecraft
[1] successfully conducted some descend operations
toward Ryugu’s surface. They included MINERVA
rover release in September, MASCOT lander release
and two touchdown rehearsals in October. During
these operations, we acquired high-resolved optical
and thermal images from altitudes below 100 m, us-
ing Optical Navigation Camera (ONC-T) and Ther-
mal Infrared Imager (TIR), respectively.
Close-up optical images by ONC-T show detailed
physical conditions of the surface materials, such as
particle size distribution of pebbles, surface morphol-
ogy of small boulders and craters. Moreover, close-up
thermal images by TIR indicate thermophysical prop-
erties of the surface materials and its regional differ-
ence, which cannot be resolved by higher altitude
observations (e.g., home-position observations from
20 km altitude). Combination between optical and
thermal observations is of great importance to under-
stand the nature of the asteroid surface materials.
In this study, we investigate the surface particle
size from close-up ONC images. Thermophysical
property of the surface component materials inferred
from TIR images is also discussed, especially for the
range observed for the thermal inertia of boulders