Theoretical Study of Accretion Disks in Close Binary Systems

封闭双星系统中吸积盘的理论研究

• 批准号: 07454036
• 负责人: OSAKI Yoji
• 金额: $ 4.42万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07454036/
• 关键词: Cataclysmic Variables; Accretion Disks; Dwarf Novae; thermal instability; tidal instability; Superoutburst; 潮汐不安定性; 不安定性; 大熊座SU型; 大熊座ER星; 超爆発

Dwarf novae are eruptive variables showing repetitive outbursts of amplitudes of 2-6 magnitude once every a few weeks to months. 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 behaviors of non-magnetic cataclysmic variable stars, starting form non-outbursting nova-like stars to various sub-classes of dwarf movae (i.e., U Gem-type, Z Cam-type, and SU UMa-type) . Furthermore, two extreme cases of SU UMa-type dwarf novae have recently been recognized : WZ Sge-type and ER UMa-type.A unification model for dwarf nova outbursts is proposed within the basic framework of the disk instability model in which two different intrinsic instabilities (i.e., the thermal instability and the tidal instability) within accretion disks play an essential role. Non-magnetic cataclysmic variables are classified into four regions in orbital-period versus mass-transfer rate diagram in different combination of stability behavior for the two intrinsic instabilities in accretion disks, and their different outburst behaviors are basically understood in this diagram. In particular, outbursts in SU UMa-type dwarf novae are understood by the thermal-tidal instability model in which the coupling of the two intrinsic instabilities in accretion disks plays a unique role. A rich variety of outburst behavior of cataclysmic variables below the period (i.e., starting from "permanent superhumpers", to Z Cam-like SU UMa stars, "ER UMa stars" , to ordinary SU UMa stars, finally to WZ Sge stars) is understood by the thermal-tidal instability model.

矮新星是一种爆发变星，每隔几周到几个月就会出现2-6等的重复爆发。目前人们普遍认为，矮新星爆发可能是由灾难性变星吸积盘的不稳定性引起的，即本文作者（Osaki, 1974）在1974年首次提出的吸积盘不稳定性模型。非磁突变变星的爆发行为丰富多样，从非爆发类新星到矮星运动的各个亚类（即U gem型、Z cam型和SU uma型）。此外，最近还发现了两种极端的SU - uma型矮新星：WZ - sge型和ER - uma型。在吸积盘不稳定性模型的基本框架内，提出了一种矮新星爆发的统一模型，其中吸积盘中的两种不同的内在不稳定性（即热不稳定性和潮汐不稳定性）起着重要作用。在吸积盘中两种本征不稳定性的不同稳定行为组合图中，将非磁突变变量划分为4个区域，基本了解了它们的不同爆发行为。特别是，SU uma型矮新星的爆发可以通过热-潮不稳定性模型来理解，其中吸积盘中两种内在不稳定性的耦合起着独特的作用。热-潮不稳定性模型可以理解周期以下突变变量的丰富爆发行为（即从“永久超级驼峰”开始，到Z凸轮类苏马星，“ER乌马星”，到普通苏马星，最后到WZ Sge星）。

项目成果

Y.Osaki: "Why Does RZ Leonis Minoris,an Unusual SU UMa Star, Have Such a Short Supercycle?" Pub1.Astron.Soc.Japan. 47. L25-L29 (1995)

Y.Osaki：“为什么RZ Leonis Minoris，一个不寻常的SU UMa明星，有这么短的超级周期？”

Osaki,Y.: "The Disk Instability Model of SU UMa Stars:Connection between the SU UMa Stars and the WZ Sge Stars." in Cataclysmic Variables,eds.A.Bianchini et al.(Kluwer Academic Publishers,Dordrecht). 307-313 (1996)

Osaki,Y.：“SU UMa 星的盘不稳定性模型：SU UMa 星与 WZ Sge 星之间的联系。”

H.Shibahashi: "A Seismic Solar Model Deduced from the Sound Speed Distribution and an Estimate of the Neutrino Fluxes" Publ.Astron.Soc.Japan. 48 (in press). (1996)

H.Shibahashi：“根据声速分布推导的地震太阳模型和中微子通量的估计”Publ.Astron.Soc.Japan。

Y.Osaki: "Dwarf-Nova Outbursts" Pub1.Astron.Soc.Pacific. 108. 39-60 (1996)

Y.Osaki：“矮新星爆发”Pub1.Astron.Soc.Pacific。

Y.Osaki: "Thermal-tidal instability model of dwarf-novae below the period gap:a unification theory" Cataclysmic Variables and Related Objects,eds.A.Evans et al.(Kluwer Academic Publishers,Dordrecht). 127-130 (1996)

Y.Osaki：“周期间隙以下矮新星的热潮汐不稳定性模型：统一理论”《灾难变量和相关天体》，A.Evans 等编辑（Kluwer 学术出版社，多德雷赫特）。