High-dispersion spectroscopy of the eclipse of epsilon Aurigae at visible and ultraviolet wavelengths.

Abstract

Visual observations: The authors report some preliminary results of the study of three photographic spectrograms obtained during the ingress, totality and egress phases and compare them with one spectrogram taken before the start of the eclipse. They describe the characteristics of the "shell" spectrum which are similar to those observed during previous eclipses. Ultraviolet observations: Comparing a set of high-resolution IUE spectra, taken at different epochs during the eclipse, the authors derive the following preliminary results. The pre-eclipse far-UV activity of March 1982 is accompanied in the mid-UV by a general rising of the continuum. The depth of the eclipse deviates very slightly from greyness. Additional deepening during the eclipse is found over the absorption wings of the Mg II λ2800 doublet. The mid-eclipse brightening seems to come from a rarefaction of the material, responsible for the continuous (grey) absorption factor.