X-ray emission from the symbiotic system CH Cygni.

Abstract

CH Cyg was observed with the EXOSAT LE1 telescope and CMA detector with 3 filters on 1985 May 24. The count rates indicate a soft X-ray spectrum with kT ≈ 0.1 keV and column density ≈4×10²⁰ cm^-2. The observed flux is ≈1.3×10^-11erg cm^-2s^-1. An earlier upper limit obtained with the Einstein Imaging Proportional Counter indicates long-term variability. Variability on a several minute timescale is found in the current data with 94% confidence. The current observations are consistent with emission from: a boundary layer between an accretion disk and an accreting white dwarf companion to the M6 III star; shocked gas formed in the collision of a fast wind from a white dwarf and the red giant wind; or a sheath of shocked gas surrounding the radio jets. If the short timescale variability is confirmed, only the first alternative is viable.