Optical properties of mm-sized fractal aggregate

Abstract

Recent observations of comets have revealed that the mm-sized fractal dust grains exist in the dust trails of comets (Ishiguro et al. 2003, ApJ. 589, L101). However, the optical property of dust is usually calculated by assuming a spherical shape. In this study, we assume as a dust grain the fractal aggregate consisting of sub-mm-sized silicate and carbon grains, where its optical properties are calculated by using a ray tracing. Moreover, we calculate an equilibrium temperature of such a large fractal aggregate by considering the equilibrium state between absorption and radiation.