SPECTRAL VARIABILITY OF THE BINARY HR-4049

The C I, Na I D, and H alpha lines of the post-AGE binary HR 4049 have been studied. Na I D variability results from a photospheric absorpti on component ([Na/H]=-1.6 +/- 0.2) which follows the velocity of the p rimary and a stationary, non-photospheric component. An emission compo nent is attributed to the circumbinary disc, and an absorption compone nt to mass-loss from the system with a velocity of 5.3 +/- 0.5 km s(-1 ). The H alpha profile varies with the orbital period. The two strong shell type emission peaks are identified as from one single broad emis sion feature with an absorption centered around -7.5 km s(-1). The int ensity variations are largely attributed to a differential amount of r eddening towards the H alpha emitting region and the stellar continuum . The radial velocities suggest that the H alpha emission moves in pha se with the primary, but with a slightly lower velocity amplitude. Fro m this we infer that the H alpha emission comes from outside the orbit of the primary, but still gravitationally bound to the primary. H alp ha also shows a weak emission feature at -21.3 +/- 3.5 km s(-1), which originates from the circumbinary disc and a weak absorption feature a t -7.5 +/- 1.6 km s(-1) due to absorption by the circumbinary disc. We propose two competing models that could account for the observed velo city and intensity variations of the H alpha profile. Model I: light f rom the primary reflects on a localized spot near the inner radius of the circumbinary disc which is closest to the primary. Model II: H alp ha emission originates in the outer layers of the extended atmosphere of the primary due to activity. These activities are locked to the pos ition of the primary in its orbit. We discuss the similarities of vari ability and shape of the H alpha emission of HR 4049 with those of ear ly type T-Tauri stars (e.g SU Aur).