A spectroscopic study of the symbiotic star AG Draconis

We present high-resolution X-ray spectroscopy of the symbiotic star system AG Draconis (AG Dra) using the Low Energy Transmission Grating Spectrograph (LETGS) on board the Chandra X-ray Observatory. AG Dra is the brightest symbiotic system in the X-ray, with soft X-ray flux nearly twice that of the next brightest system, making it an ideal laboratory to study symbiotic stars. We fit the the spectrum of AG Dra with an absorbed blackbody model and measure the absorption, temperature, and luminosity of the hot component of the system. In addition, we detect emission lines from ionized S, P, Mg, and Fe. We explore evidence for an accretion disk surrounding the white dwarf, with wind accretion and a collisional plasma component, and find our results are consistent with theoretical simulations of symbiotic systems like AG Dra, which predict the formation of an accretion disk that accretes mass through Bondi-Hoyle-Lyttleton accretion.