Behind the Iron Curtain: The Environments of the Iron Stars AS 325 and XX Oph

摘要

We present new photometric and spectroscopic observations of the Iron stars AS 325 and XX Oph. Both stars are binaries composed of a Be star primary plus a luminous red star. Long-term optical photometry of AS 325 reveals it to be a 513-day period eclipsing binary with highly variable eclipses. The primary eclipse is that of the Be star with no secondary eclipse observed. This is not surprising given the small comparative size of the more massive companion. The red star in AS 325 is observed to be a variable star ranging from K2.5 to a M5 in spectral type and shown to be a supergiant of luminosity class II. The red secondary star is the major cause of the variable eclipses. A simple model is advanced to explain the complex behavior observed for Balmer hydrogen emission and Ca II H and K absorption lines as a function of eclipse phase. Spatially resolved near-IR spectroscopy of XX Oph shows the binary to be sitting in a large cavity-like region of space surrounded by reflective dust. AS 325 and XX Oph are nearly identical binary systems.