Mass loss rates for Wolf-Rayet stars from radio continuum observations

Wolf-Rayet (W-R) stars are now generally regarded as the evolutionary products of O stars which by some process of mass loss have shed their outer hydrogen layer and exposed the helium core. The mass loss phenomenon in W-R stars must be understood before the temperature, luminosity, chemical composition, and evolutionary status of these stars can be determined with any certainty. The present investigation is concerned with a survey of mass loss rates from 13 W-R stars by measuring free-free emission at radio wavelengths. Radio emission is detected from eight of the stars which were observed at 5 GHz with the Very Large Array (VLA). The presence of a binary companion appears to have little or no effect in terms of enhancing the mass loss rate, although the statistics are poor.