Astrometry of red supergiant VY Canis Majoris with VERA

摘要

We present observational results on the red supergiant VY Canis Majoris withVERA. We have observed 22 GHz H20 masers and 43 GHz SiO masers (v=1 and 2 J=1-0)around VY CMa for 13 months. We succesfully detected a parallax of 0.87 ± 0.08 mas, corre-sponding to the distance of 1.15 kpc using H20 masers. As the result of phase-referencinganalyses, we have measured absolute positions for both H20 masers and SiO masers. The 1120maser features show rapid expansion off the central star.