Completion of Unification Model for the Outburst Mechanism of Dwarf Novae

矮新星是一种爆发性变星，每隔几周到几个月就会重复爆发一次，振幅为3-5级。矮新星属于被称为激变变星的近距离双星系统，其中充满罗奇瓣的红矮星次级星星失去质量，白色初级星星通过吸积盘吸积它。现在人们普遍认为矮新星的爆发可能是由激变变星吸积盘的不稳定性引起的：即，本文作者（大崎，1974）于1974年首次提出的盘不稳定性模型。各种矮新星的爆发光变曲线有着丰富的变化。1996年，作者在盘不稳定性模型的基本框架内提出了矮新星爆发的统一模型。本研究的目的是通过从多个角度对这一模型进行研究来完成这一项目。总结本学期的研究成果. X射线辐射日冕模型 关于我们 d激变变星中的白色矮星众所周知，如果吸积速率低于某个临界值，由于边界层的热不稳定性，在吸积白色矮星周围会产生近球形的热日冕。建立了该日冕的稳态模型，并计算了X射线谱随质量供应率的变化。已经发现日冕的热能通过电子传导向下传输到靠近白色矮星表面的密度更大的区域，在那里它以X射线辐射的形式发射出来。大约5%的物质可以以恒星风的形式离开系统。完成了矮新星爆发机制的统一模型我们的矮新星爆发机制的统一模型在盘不稳定性范式下由我自己在各种国际研讨会和讲习班上提出。这一理论得到了广泛的认可，但也有一些批评意见，这些批评意见将有助于这一理论的进一步发展。少

Dwarf novae are eruptive variables showing repetitive outbursts of amplitudes of 3-5 magnitude once every a few weeks to months. Dwarf novae belong to close binary systems called cataclysmic variable stars in which a Roche-lobe filling red dwarf secondary star loses mass and a white dwarf primary star accretes it via an accretion disk. It is now widely accepted that outbursts of dwarf novae may be caused by the instability in accretion disks in cataclysmic variable stars: i.e., the disk instability model which was first proposed by the present author (Osaki, 1974) in 1974. There is a rich variety in outburst light curves of various dwarf novae. A unification model for dwarf nova outbursts was proposed by the present author in 1996 within the basic framework of the disk instability model. The purpose of this research is to complete this project by investigating this model from various standpoint. Research results in this term will be summarized.1. A model of X-ray emitting coronae aroun … More d a white dwarf in cataclysmic variable starsIt is known that a nearly spherical hot corona is produced around accreting white dwarfs because of thermal instability at the boundary layer if the accretion rate is below some critical value. A steady state model of this corona is constructed and the X-ray spectra are calculated as functions of the mass supply rate. It has been found that the thermal energy of the corona is transported downward by electron conduction to the denser area near the surface of the white dwarf, where it is emitted as X-ray radiation. Around 5% of the matter supplied by the disk could leave the system as stellar wind.2. Completion of unification model for the outburst mechanism of dwarf novaeOur unification model for the outburst mechanism of dwarf novae within the disk instability paradigm was presented by myself in various international symposia and workshops. It was generally accepted warmly but several criticisms were also raised sometime and these will be useful for further development of this theory. Less