ub-arc second (- 0'.'15) VLA observations at 2 em have resolved the previously reported 6 em H II region, which engulfs the R Aquarii binary system, into two components. The stronger 2 em component is itself partially resolved (distorted in shape), which may be a consequence of the long-period variable (LPV) wind being subjected to the intense ionizing radiation field of the hot companion's accretion disk, which we suspect is precessing. The distorted radio contours of the central H II region may also suggest that one hemisphere of the extended LPV envelope is directly illuminated by the intense radiation field of the accretion disk, owing to the orientation of the disk. The accretion disk can be formed by tidal mass exchange between the LPV and hot companion, which results in blobs of material periodically being expelled primarily in the northeast direction. Together with the VLA results, we report SiO observations obtained with the Hat Creek interferometer that suggest maser action occurs in the circumbinary nebulosity far removed from the LPV photosphere.
Hollis, J.M., Michalitsianos, A.G., Kafatos, M., Wright, M.C.H., Welch, W.J. (1986) Sub-Arc Second 2 Centimeter Continuum and SiO Spectral Line Observations of R Aquarii, The Astrophysical Journal, 309: L53-L57. doi: 10.1086/184759