Dust formation around HD 193793

Abstract

The paper deals with observations (between November 1976 and June 1977) of a sudden infrared brightening of the Wolf-Rayet star HD 193793 by 2.5 mag at 2.3 microns and by 1.3 mag at 10 microns. The event was followed by a slow decline at 2.3, 3.6, and 4.9 micron and a slow brightening at 8.6 micron and longer wavelengths. The analysis leads to the conclusion that the infrared excess may be attributed to emission from circumstellar dust (possibly iron) which condensed about the star in mid-1977).