We have used the VLBA to conduct a monitoring campaign of the total intensity and polarization structure of the 43 GHz, ν = 1, J = 1-0 SiO masers from three late-type stars. Our data reveal that rings and arcs of emission are the prevalent total intensity structure observed. Coherent structures are also evident in the linearly polarized emission. Dramatic structural variations are common: images taken 6 months apart often bear little relationship to each other. Based on circular polarization measurements we estimate the typical magnetic field strength at the position of the SiO masers to be ∼5-10 G.
ASJC Scopus subject areas
- Astronomy and Astrophysics