X-rays from the Symbiotic Star RX Pup

Abstract

We describe X-ray and optical observations of the symbiotic star RX Pup. From low resolution optical spectra, we obtain a reddening for RX Pup of E(B − V ) = 0.79. We use the neutral column density corresponding to this reddening as a lower limit for the X-ray spectra fits. The X-ray spectra can be fitted with either a two-temperature thermal plasma model or a single-temperature plasma plus a narrow line at ≈0.55 keV, each modified by interstellar absorption. The RX Pup X-ray flux is not variable within the observation exposure time, suggesting that unlike in most CVs, an accretion disk boundary layer does not contribute significantly to the X-ray flux. Instead, the X-ray emission may come from shock-heated gas further away from the compact object.