THE DIFFUSE INTERSTELLAR BANDS .8. NEW FEATURES BETWEEN 6000-A AND 8650-A

Twenty-two new diffuse interstellar bands (DIBs) have been discovered on high signal-to-noise Reticon scans of reddened O- and B-type stars in the 5840-8650 angstrom region, with special attention being given to HD 183143 (B7 Ia). Most of the new DIBs occur in regions masked by atmospheric O2 and H2O. Attempts to find DIBs at positions expected for a transition in the (hypothetical) spectrum of interstellar H-, and at wavelengths of lines in the laboratory spectrum of Cr3+:MgO, were inconclusive. A systematic search was made in the wavenumbers of the 105 DIBs now known for vibrational sequences of the type 0 --> upsilon'; none of those found are very convincing. The large number of DIBs now known, far more than would be expected in the spectrum of a single species at interstellar temperatures, must mean that a substantial number of different carriers are responsible for the DIB spectrum.