Mass loss from evolved stars. III - Mass loss rates for fifty stars from CO J = 1-0 observations

Abstract

The authors present observations at 2.6 mm wavelength of the CO J = 1-0 line made with the Bell Laboratories 7 m antenna in the directions of 105 cool, evolved stars having envelopes produced by mass loss. Emission was detected from 50 stars, of which about half are M-type Mira variables, half are carbon or S stars, and two are supergiants. Twenty of these envelopes are detected for the first time in the CO (1-0) line. The data are used to derive values for the stellar systemic velocity, the terminal outflow velocity of the wind, and the mass loss rate Mfor the envelopes. The values of Mderived from CO observations cover a range of ≡10-7 to a few×10-4M_sun;yr-1. A preliminary estimate of the total galactic rate of mass return to the interstellar medium by such stars gives MT ≡ 0.3 M_sun;yr-1.