Rocket-Borne Observations of the Zodiacal Light in the Near-Infrared Wavelengths

Abstract

Our recent rocket-borne observations have provided valuable information on the near-infrared feature of the zodiacal light at high ecliptic latitude and large solar elongation. The observed spectra at λ < 2.5 μm where the zodiacal light dominates the sky brightness are smooth without significant line features and much redder than the solar color. The observed color of the zodiacal light and the estimated albedo of interplanetary dust are comparable to those of Comet Halley. This suggests that cometary dust contributes considerably to interplanetary dust. The intensity profile of near-infrared zodiacal light as a function of the ecliptic latitude is flatter than at the visible wavelength. Dust properties which could reproduce the observed profile are discussed.