VLA radio continuum measurements of mass loss from early-type stars

Mass loss rates derived from 6 cm flux density observations of 15 O-, B-, and A-type stars are reported which rule out the nearly linear proportionality between mass loss and stellar luminosity previously proposed. They are, however, consistent with relation of mass loss being equal to 1.4 x 10 to the -16th power times (L/L(solar))(to the 1.8th power) solar mass/yr. The majority of the obtained values agree to within a factor of three with rates previously derived from infrared, optical and ultraviolet observations, but the radio mass loss rate from 9 Sgr, that is, 2 x 10 to the -5th solar mass/yr, is a factor of 40 greater than that obtained from the analysis of UV and optical data. This contradicts the hypothesis that the rate of mass loss increases as a star evolves from the main sequence from O to Of type stars.