MOLECULAR DIFFUSE INTERSTELLAR BAND CARRIERS IN THE RED RECTANGLE

High-resolution optical spectroscopic observations of unidentified emi ssion bands from the unusual biconical nebula known as the Red Rectang le are reported. The peak wavelengths and the widths of prominent band s near 5799, 5853, and 6616 angstroms decrease with increasing offset from the central A0-type star HD 44179 and, in the limit of large dist ance from the star, are shown to converge toward the known values for some of the narrower diffuse interstellar absorption bands at 5797, 58 50, and 6614 angstroms, The same carriers give rise to both Red Rectan gle emission and corresponding diffuse interstellar absorption bands, and these particular bands arise from electronic transitions in gas-ph ase molecules.