A VLBI polarization study of SiO masers towards VY CMa

Abstract

Maser emission from the SiO molecule has been widely observed in the near-circumstellar envelopes of late-type, evolved stars. VLBI images can resolve individual SiO maser spots, providing information about the kinematics and magnetic field in the extended atmospheres of these stars. This poster presents full polarization images of several SiO maser lines towards the supergiant star VY CMa. VY CMa is a particularly strong SiO maser source and allows observations of a wide range of maser transitions. We discuss implications of these observations for VY CMa morphology, polarization, and pumping models.Comment: 3 pages, 1 figure: based on a poster paper at IAU Symposium 242: Astrophysical masers and their environments, held at Alice Springs (Australia), from March 12-16, 200