The Turn-off of Classical Novae Observed Through X-rays: Models versus ROSAT Observations of V1974 Cyg

Detection of X-ray emission from classical novae in their post-outburst stages provides crucial information about the nova phenomenon. The soft X-ray emission gives a direct insight into the remaining hot nuclear burning shell. A numerical model for steady H-burning white dwarf envelopes has been developed to study the post-outburst phases of classical novae. Properties of the X-ray emission of the post-nova white dwarf are obtained, and the results are compared to ROSAT observations of V1974 Cyg.