Completion of Unification Model for the Outburst Mechanism of Dwarf Novae

矮新星爆发机制统一模型的完成

基本信息

批准号：
10640226
负责人：
OSAKI Yoji
金额：
$ 1.98万
依托单位：
Nagasaki University (1999)The University of Tokyo (1998)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640226/
关键词：
Dwarf Novae Cataclysmic Variables Accretion Disks Close Binary System X-ray Radiation Corona

项目摘要

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

矮新星是爆发性变星，每几周到几个月就会出现一次 3-5 星等的重复爆发。矮新星属于称为灾变变星的紧密双星系统，其中一颗罗氏瓣填充的红矮星次级恒星失去质量。矮主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吸积盘的不稳定性引起的。灾变变星中的吸积盘：即本作者（Osaki，1974）于1974年首次提出的吸积盘不稳定模型。各种矮新星的爆发光曲线有丰富的多样性。矮新星爆发的统一模型。是本作者于1996年在盘不稳定性模型的基本框架内提出的。本研究的目的是完成这个项目。通过从不同的角度研究这个模型，将总结本学期的研究结果。 1. 灾难性变星中白矮星周围发射 X 射线的日冕模型已知，在吸积白矮星周围会产生近乎球形的热日冕。如果吸积率低于某个临界值，则由于边界层的热不稳定，会出现矮星。构建了该日冕的稳态模型，并计算了 X 射线光谱作为的函数。研究发现，日冕的热能通过电子传导向下传输到白矮星表面附近的致密区域，并以 X 射线辐射的形式发射出来。 2．完成矮新星爆发机制的统一模型提出了盘不稳定范式下矮新星爆发机制的统一模型。我本人在各种国际研讨会和研讨会上提出的这一观点得到了普遍的热烈欢迎，但有时也提出了一些批评，这些对于该理论的进一步发展是有用的。