Toward the evidence of the accretion disk emission in the symbiotic star RR telescopii

In this Letter, we argue that in the symbiotic star RR Telescopii, the existence of an accretion disk around the hot companion is strongly implied by the characteristic features exhibited by the Raman-scattered O vl lines around 6830 and 7088 Å. High degrees of polarization and the double-peaked profiles in the Raman-scattered lines and the single-peak profiles for other emission lines are interpreted as line-of-sight effects, where the H I scatterers near the giant star see an incident double-peaked profile and an observer with a low inclination sees single-peak profiles. It is predicted that different mass concentrations around the accretion disk that is formed by a dusty wind may lead to the disparate ratios of the blue peak strength to the red counterpart observed in the 6830 and 7088 Å features. We discuss the evolutionary links between symbiotic stars and bipolar proto-planetary nebulae and conclude that the Raman-scattering processes may play an important role in the investigation of the physical properties of these objects.