N. C. Wickramasinghe

Unified model for interstellar extinction and polarization.

THE development of improved techniques for measuring interstellar extinction and polarization has led to a revival of interest in the investigation of grain models. The interstellar extinction curve has recently been extended by Stecher1, using rocket techniques, as far as ∼ 1200 Å in the far ultra-violet. It has already become clear that the conventional dirty ice grain model must be ruled out for several reasons. This model cannot explain the detailed shapes of the extinction curves for the visible spectral region obtained by Nandy2; nor can it reproduce even the qualitative features of the near and middle ultra-violet observations3,4.