Radial velocities and fluxes of the main components of the Hα profile as a function of time during the fireball stage (see Sect. 3.3). Fluxes are in 10^-11 erg cm^-2 s^-1. a) Radial velocities of separated (filled squares) and observed (empty boxes) absorption components. b) Flux absorbed by the Hα line. c) Flux emitted by the separated components (from Aug. 18.91 on, it also includes the broad emission wing).