Magnetic fields in the envelopes of late-type stars: circular polarization of H2O masers.

We present the first circular polarization measurements of circumstellar H2O masers around a sample of late-type stars. These observations are used to obtain the magnetic field strength in the H2O maser region with both an LTE and non-LTE anal. We find fields from a few hundred milliGauss up to a few Gauss, indicating a solar-type r-2 dependence of the magnetic field on the distance. No linear polarization is detected to less than 1%. [on SciFinder (R)]