First results of UVES at VLT: revisiting RR Tel

Abstract

We present here the first results of UVES observations of RR Tel. The exceptional performances of the instrument have allowed the detection of new spectral features and have led to an improvement in the identifications of several emission lines. A direct comparison with the IUE observations in the range 3045-3300 A has revealed the appearance of many weak and shallow lines, most of them lacking a convincing identification. The Balmer lines are visible up to H38 and are accompanied by the He II lines of the Pickering series. Also, all of the He II emissions of the Pfund series, from 5858 A to 6408 A have been detected. We made definite identifications of additional TiO bands at 4955 A (alpha R_2 1-0), 5167 A (alpha R_2 0-0), 5445 A (alpha R_2 0-1), 5598 A (beta R_1 0-0), 5847 A (gamma 'R_1 1-0), and 6148 A (gamma ' {^S} R_21 0-0). The Halpha line has very wide wings, extending to at least 5000 km/s, which are similar to those reported for the planetary nebula IC 4997 and attributed to Raman scattering by Ly beta photons. A selective pumping mechanism via the HeII 237 A emission is proposed to explain the intensity of the high-lying lines of O IV mult. 1 and 2.