Sub--Arc Second 2 Centimeter Continuum and SiO Spectral Line Observations of R Aquarii

Sub-arc second (≡0arcsec.15) VLA observations at 2 cm have resolved the previously reported 6 cm H II region, which engulfs the R Aquarii binary system, into two components. The stronger component is itself partially resolved and 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. The accretion disk, which may be precessing, can be formed by tidal mass exchange between the LPV and its hot companion. The authors also report SiO observations that suggest maser action occurs in the circumbinary nebulosity far removed from the LPV photosphere.