Polarization properties of the 86.2 GHz V = 1, J = 2 - 1 SiO maser

Abstract

Complete Stokes parameters have been measured for a small sample of SiO masers associated with variable stars. These sources were found to be typically 15-30% linearly polarized and to exhibit no circular polarization above limits of as low as a few percent. The Orion Molecular Cloud source exhibited no linear or circular polarization greater than 3% during the present observing period. The Stokes parameters for R Cas, not necessarily including the total intensity, were found to vary over short periods. Comparison of the profiles for regular variable stars with those obtained several optical periods earlier reveals substantial changes. No apparent correlation exists between these changes and the optical variations of the stars.