Published online by Cambridge University Press: 03 August 2017
We briefly report the results of polarimetric observations of SiO emission from late-type stars taken with a millimeter polarimeter installed at the Nobeyama 45m telescope. We found that the SiO J = 2 − 1 emission in the v = 0 state from R Cas contains a highly linearly polarized component, followed by the detection of highly linearly polarized emission of the same transition from VY CMa (Shinnaga et al. 1999). The high polarization degree is a strong evidence that the v = 0 emission originates from maser action. We found out that, not only a peculiar supergiant star, but also a Mira variable star is associated with the SiO v = 0 maser.