Hubble Space Telescope images of the compact nebula around RY Scuti

We present HST Wide Field Planetary Camera 2 images of the very massive eclipsing binary RY Scuti. The HST Hα image shows a very complex ionized nebula roughly 1″ in size. Several interesting structures are revealed, including what appears to be a pair of concentric ionized rings above and below the equatorial plane of the system, located at the inner edge of a more extended dust torus. We reexamine some essential physical characteristics of the nebula, such as a possible magnetic field and the complicated mass-loss geometry of this near-Eddington limit contact binary. The effects of a rotating illumination source are considered to explain the brightness distribution in the rings. We suggest a model for the origin of the mass and detailed structure in the nebula. This model invokes a previous mass ejection that is shaped by nonspherical interacting winds and possibly magnetic fields.