Nebular emission lines in IRAS 17347-3139
  We report the detection of nebular emission lines in the optical and mid-infrared spectra of IRAS 17347-3139, a heavily obscured OH/IR star which may be rapidly evolving from the AGB to the PN stage. The presence of emission lines is interpreted as a clear indication that the ionization of its circumstellar envelope has already started. This source belongs to the rare class of objects known as `OHPNe' displaying both OH maser and radio continuum emission. However, unlike the rest of stars in this class, prominent C-rich dust features are detected in its mid-infrared spectrum, which makes the analysis of this star particularly interesting. 
F.M. Jim\'enez-Esteban, J.V. Perea-Calder\'on, O. Su\'arez, M.   Bobrowsky, P. Garc\'ia-Lario