Japan Geoscience Union Meeting 2015

Presentation information


Symbol P (Space and Planetary Sciences) » P-PS Planetary Sciences

[P-PS24] Origin and evolution of materials in space

Wed. May 27, 2015 11:00 AM - 12:45 PM A02 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Shogo Tachibana(Department of Natural History Scieces, Hokkaido University), Hitoshi Miura(Graduate School of Natural Sciences, Department of Information and Biological Sciences, Nagoya City University), Takafumi Ootsubo(Graduate School of Arts and Sciences, University of Tokyo), Mitsuhiko Honda(Department of Mathematics and Physics, Kanagawa University), Chair:Shogo Tachibana(Department of Natural History Scieces, Hokkaido University)

11:45 AM - 12:00 PM

[PPS24-04] Small-scale structure of the zodiacal dust cloud observed in mid- and far-infrared with AKARI

*Takafumi OOTSUBO1, Fumihiko USUI1 (1.The University of Tokyo)

Keywords:zodiacal light, interplanetary dust, AKARI, infrared

The zodiacal light emission (ZE) is the thermal emission from the interplanetary dust and the dominant diffuse radiation in the mid- to far-infrared wavelength region. The zodiacal dust cloud has a relatively smooth distribution. However, from the results of the Infrared Astronomy Satellite (IRAS) observations, it was found that there are many small-scale structures in the ZE distribution, such as asteroidal dust bands and a circumsolar resonance ring.

The Japanese infrared satellite AKARI, a dedicated satellite for infrared astronomical observations, is the mission to survey the whole sky in the mid- and far-infrared. AKARI detected the small-scale structure of the zodiacal cloud, such as the asteroidal dust bands and the circumsolar ring. There are three major bands (±1.4 degree, ±2.1 degree, and ±9.3 degree) among dust bands that form small-scale latitude features in the ZE. These three prominent asteroidal dust bands can be clearly seen in the AKARI far-infrared all-sky maps at 65 and 90 micron bands.

We also present spectra of the zodiacal light observed in mid-infrared wavelength region with Infrared Camera (IRC) onboard AKARI. The IRC spectra (5.5--12.5 micron) show a trapezoidal excess emission feature in 9--11 micron region which can be reasonably accounted for by a combination of amorphous and/or crystalline silicate. Although this excess feature is rather smooth and lacking sharp peaks, a possible 10.5 micron peak and small peaks around 9.3 and 11.35 micron can be seen at the shoulder of the trapezoidal excess. The spectrum around β=10 degree toward the asteroidal dust band seems to have a slight different shape of the silicate feature from those of other regions.