Rocket observations of mass loss from hot stars

Rocket observations have shown that the far-ultraviolet resonance lines have P-Cygni profiles in the spectra of many hot stars, including of and Wolf-Rayet stars and OB supergiants. Velocity shifts as high as–300- km sec^–1 have been measured for the short-wavelength edges of some of the lines. Estimates of the rates of mass loss range from 10^–8 to 10^–6 M year^–1.Presented at the Trieste Colloquium on Mass Loss from Stars, September 12–16, 1968.