High-dispersion spectrographic data are described for 65 very luminous galactic OB stars.
Their absolute magnitudes and masses are estimated. Almost all the stars show evidence
for mass outflow, and the flow rate is empirically calibrated from mass-loss models for a few
of them. Approximate contours of mass-loss on the HR diagram are suggested which
support the zero point of the individual rates. These are as high as one hundred-thousandth
of a solar mass per year from a supergiant of 60 solar masses. Anomalously high mass-loss …