X-ray Observations of Novae

摘要

X-ray studies of classical novae which were performed by EXOSAT, ROSAT and most recently by BEPPOSAX, CHANDRA and XMM have turned out to be a very powerful tool to study the hot phases in the outburst of a classical nova. Only X-ray data provide unambiguous information on the evolution of the thermonuclear runaway. X-ray studies so far have identified both a soft component originating on the hydrogen burning white dwarf and a hard component from hot circumstellar material due to shocks in the nova outflow. In addition, emission lines from highly ionized species found in spectra with higher resolution have been observed allowing plasma diagnostics for the hot regions. Here the X-ray observations carried out so far and their implications to our understanding of the nova outburst will be reviewed.