The Spectrum of the Blue Luminescence in the Red Rectangle
Abstract
Recently, we announced the discovery of blue luminescence (BL) emission in the spectrum of the proto-planetary Red Rectangle (RR) nebula (Vijh et al. 2004) and suggested the attribution of this phenomenon to fluorescence by small, neutral PAH molecules, 3 to 4 rings in size (Vijh et al. 2005a). BL spectra of similar shape and intensity were also detected in several ordinary reflection nebulae illuminated by early-type stars (Vijh et al. 2005b), suggesting that the emitting particles are common within the ISM. The study of the BL spectrum and its variation with environmental factors is complicated due to the dominance of the dust-scattered light. The presence of an optically thick circumstellar disk seen edge-on in the RR, however, reduces the scattered light intensity by a factor of ~40. This has permitted us to observe the molecular band structure of the BL in the RR for the first time. A series of seven distinct emission bands centered at the wavelengths 377.5 nm, 392.9 nm, 407.7 nm, 423.7 nm, 438.8 nm, 451.6 nm and 465.2 nm has been detected, superimposed upon a broad emission continuum. We will discuss the spatial variability of the BL intensity and its spectrum within the RR and will discuss possible identifications of the emitting molecules.
- Publication:
-
Astrochemistry: Recent Successes and Current Challenges
- Pub Date:
- 2005
- Bibcode:
- 2005IAUS..231P.234V
- Keywords:
-
- ISM: individual: HD 44179;
- ISM: individual: Red Rectangle;
- ISM: lines and bands;
- ISM: molecules;
- ISM: reflection nebulae;
- radiation mechanisms: nonthermal;
- techniques: spectroscopic