Theoretical and Observational Studies of the Nova Outburst

斯塔尔菲尔德9417057新星发生在激变的双星系统中，在这个系统中，一个充满罗氏叶的次级天体正在通过内部拉格朗日点失去富氢物质，进入白矮星初级星系。白矮星上堆积的物质壳对热核失控是不稳定的，对这一现象的流体动力学模拟重现了许多观测到的新星爆发特征。这项研究分为两个主要领域：经典新星爆发的理论研究和使用Pi-S流体动力学-核合成恒星演化程序+新的辐射-流体动力学程序的相关课题，以及支持理论研究的光学观测研究。理论上要回答的问题是：(1)由于几乎所有被研究得很好的新星在爆炸时喷出的物质中都显示出丰富的核丰度，这种丰度的来源是什么？(2)由于许多新星显示出富含氧气、霓虹和镁的喷射物，OneMG白矮星被吸积的后果是什么？为什么这些新星会喷出如此多的物质？(3)既然V1500天鹅座和GQMus都被确定为含有磁化的白矮星(AM她的变量)的双星系统，强磁场对这次爆发的影响是什么？(4)由于ROSAT和IUE卫星对新星的观测现在已经测量了V1974天鹅座和GQMus的关闭时间，那么白矮星停止核燃烧和恢复静止的原因是什么？(5)由于我们现在已经收集了一些最近新星如V1974 Cyg，Cas 1993和LMC 1990#1爆发的极好的数据，我们如何能够很好地模拟这些新星的爆发？(6)由于所有快速新星似乎都经历了一个超级爱丁顿光度阶段，产生这一阶段的关键因素是什么？最后，将继续进行光学观测，以研究新星在爆发中的演化，并确定能量、元素丰度和关闭时间。***

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. ***