Japan Geoscience Union Meeting 2019

Presentation information

[J] Oral

P (Space and Planetary Sciences ) » P-CG Complex & General

[P-CG23] Origin and evolution of materials in space

Sun. May 26, 2019 9:00 AM - 10:30 AM 201B (2F)

convener:Hitoshi Miura(Graduate School of Natural Sciences, Department of Information and Basic Science, Nagoya City University), Hideko Nomura(Department of Earth and Planetary Sciences, Tokyo Institute of Technology), Takafumi Ootsubo(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Aki Takigawa(Division of Earth and Planetary Science, Kyoto University), Chairperson:Ryo Tazaki, Aoi Takahashi

10:00 AM - 10:15 AM

[PCG23-05] Shape dependence of dust absorption opacity in the Rayleigh domain

*Ryo Tazaki1, Hidekazu Tanaka1 (1.Astronomical Institute, Tohoku University)

Keywords:Non-spherical dust particles, Absorption opacity, T-Matrix Method

In various astrophysical environments, dust absorption opacity must be assumed to estimate dust mass by observations. Cosmic dust particles often have radii smaller than FIR or more longer wavelengths, and hence, they are typically in the Rayleigh domain at these observing wavelengths. It is known that absorption opacity in the Rayleigh domain sensitively depends on the shape of dust particles. In this study, we study how dust coagulation alters absorption opacity in the Rayleigh domain by using the T-Matrix Method. We find that higher-order terms of harmonic expansion of the electromagnetic field must be taken into account to reproduce strong field appearing around contact points between monomer particles. As a result, we show that coagulation can enhance dust absorption opacity by a factor of about 2 for silicate and about 5 for carbonaceous particles. We discuss appropriate approximate methods to mimic the shape effect of dust absorption opacity.