Interpretation of Doppler Shifts in the Zodiacal Light Spectrum

Abstract

Reay and Ring¹ have recently presented measurements of Doppler shifts in the spectrum of the evening zodiacal light obtained in the plane of the ecliptic. They compare the data with the assumption that the interplanetary dust particles are in direct circular orbits, the number density of dust particles varying with heliocentric distance, r, as r^−β, where β = 3. The agreement between theory and observations is imperfect; nevertheless, their suggestion about the dust density is of great importance to an understanding of the origin of the zodiacal dust cloud. We have therefore tried to obtain an improved fit to these observations by using a more general distribution of the orbital parameters of the dust particles in the hope of drawing a more definite conclusion concerning the value of β.