Sentence:  Zodiacal light and the gegenschein give some evidence for such a dust blanket , a phenomenon also to be expected if the dust before capture is in circular <WSD>orbits</WSD> about the sun , as indicated by the trend of the smaller visible meteors . 
Meaning of the word marked with <WSD> tags:  the (usually elliptical) path described by one celestial body in its revolution about another