Study of the interplanetary dust at high ecliptic latitudes: Doppler-Fizeau shifts

Measurements of the Doppler shifts in the zodiacal light spectrum have already been performed by James and Smeethe (1970) and more recently by Fried (1978). The results showed that dust grains of the zodiacal cloud are on prograde orbits around the Sun, but with velocities higher than what was expected: hyperbolic type velocities were found at small heliocentric distances. Using a different method of observation, the authors' purpose is to obtain direct spectra of the light scattered by the dust grains, in order to measure the observed, averaged along the line of sight, Doppler shifts at high ecliptic latitudes. (Auth.)