Although the prevalent mathematical description of the Poynting-Robertson e
ffect is correct, its physical interpretation is sometimes problematic. By
means of a two-parameter model, we revisit the effect in order to get a bet
ter physical understanding of it. The principal conclusion is that the moti
on of a dust in circumsolar orbit is governed only by solar radiation absor
ption and not by the asymmetry of reemission, even when viewed in the rest-
frame of the Sun. (C) 1999 Academic Press.