Starrfield 9417057 Novae occur in cataclysmic binary systems in which a Roche lobe filling secondary is losing hydrogen-rich material through the inner Lagrangian point onto a white dwarf primary. The accumulating shell of material on the white dwarf is unstable to a thermonuclear runaway and hydrodynamic simulations of this phenomenon reproduce many of the observed features of the nova outburst. The proposed research falls into two main areas: theoretical studies of the classical nova outburst and related topics using both the PI s hydrodynamic-nucleosynthesis stellar evolution code plus a new radiation-hydrodynamic code and, in addition, optical observational studies in support of the theoretical investigations. The questions to be answered theoretically are: (1) Since virtually all well studied novae exhibit enriched nuclear abundances in the material ejected by the explosion, what is the source of that enrichment? (2) Since many recent novae exhibit ejecta enriched in oxygen, neon, and magnesium, what are the consequences of accretion onto ONeMg white dwarfs and why do these novae eject so much material? (3) Since both V1500 Cygni and GQMus have been identified as binary systems containing magnetized white dwarfs (AM Her variable), what are the consequences of strong magnetic fields on the outburst? (4) Since observations of novae by the ROSAT and IUE satellites have now measured the turn off times for V1974 Cygni and GQMus, what is the cause of the cessation of nuclear burning and the return to quiescence of the white dwarf? (5) Since we now have superb collections of data on the outbursts of a number of recent novae such as V1974 Cyg, Cas 1993, and LMC 1990#1, how well can we simulate the outbursts of these novae? (6) Since all fast novae seem to experience a phase of super-Eddington luminosity, what are the critical factors that produce this phase? Finally, optical observations to study the evolution of novae in outburst and determine energy b udgets, elemental abundances, and turn off times will be continued. ***
