  Interplanetary dust (IPD) scatters solar radiation which results in the
zodiacal light that dominates the celestial diffuse brightness at optical and
near-infrared wavelengths. Both asteroid collisions and cometary ejections
produce the IPD, but the relative contribution from these two sources is still
unknown. The Low Resolution Spectrometer (LRS) onboard the Cosmic Infrared
Background Experiment (CIBER) observed the astrophysical sky spectrum between
750 and 2100 nm over a wide range of ecliptic latitude. The resulting zodiacal
light spectrum is redder than the solar spectrum, and shows a broad absorption
feature, previously unreported, at approximately 900 nm, suggesting the
existence of silicates in the IPD material. The spectral shape of the zodiacal
light is isotropic at all ecliptic latitudes within the measurement error. The
zodiacal light spectrum, including the extended wavelength range to 2500 nm
using IRTS data, is qualitatively similar to the reflectance of S-type
asteroids. This result can be explained by the proximity of S-type asteroidal
dust to Earth's orbit, and the relativily high albedo of asteridal dust
compared with cometary dust.
