Analysis of P Cygni line profiles - Generalization of the nth order moment WN

The generalization of the nth order moment W[SUB]n[/SUB] of a P Cygni line profile leads to a new approach of deriving the various physical quantities which characterize the phenomenon of mass-loss around stars, quasars, etc. Adopting realistic expressions for the velocity and opacity distributions the author presents and discusses the results of calculations of the moments W[SUB]n[/SUB] in two types of different diagrams: the "log (W[SUB]n[/SUB])-log(W[SUB]n[/SUB][SUP]0[/SUP])" and "log(W[SUB]n[/SUB])-log (W[SUB]0[/SUB])" diagrams. The physical representation of the parameters W[SUB]n[/SUB][SUP]0[/SUP] is then given and the author tests and generalizes the validity of some of the linear relations W[SUB]n[/SUB] â W[SUB]n[/SUB][SUP]0[/SUP] for the case of slowly expanding optically thin atmospheres.