Physics of nova outbursts: Theoretical models of classical nova outbursts with optically thick winds on 1.2 M⊙ and 1.3 M⊙ white dwarfs.

This article focuses on time-dependent models of classical nova outbursts on accreting white dwarfs (WDs) with masses of 1.0, 1.2, 1.3, and 1.35 solar masses (|$M_{\odot}$|), incorporating optically thick winds and detailed energy budgets. The models simulate the evolution from thermonuclear runaway through the X-ray flash phase to optical maximum, showing that more massive WDs have shorter timescales to optical peak and higher X-ray luminosities, with nuclear energy primarily emitted as radiation and gravitational energy of ejecta. An empirical relation is derived linking the expansion timescale of the envelope to the time to optical maximum, enabling prediction of nova rise times from early ignition parameters without full wind evolution calculations. The study also supports the presence of internal shocks in nova ejecta after optical maximum and provides theoretical context for the recent detection of an X-ray flash in the classical nova YZ Ret, consistent with a massive WD and hydrostatic envelope prior to wind onset.