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.

矮新星是爆发性变量，每几周到几个月就会重复爆发一次 2-6 级的振幅。现在人们普遍认为，矮新星的爆发可能是由灾变变星吸积盘的不稳定性引起的：即本作者（Osaki，1974）于1974年首次提出的吸积盘不稳定性模型。非磁灾变变星爆发行为的多样性，从非爆发类新星到各种矮星 movae 的子类（即 U Gem 型、Z Cam 型和 SU UMa 型）。此外，最近还认识到了 SU UMa 型矮新星的两种极端情况：WZ Sge 型和 ER UMa 型。在盘不稳定模型的基本框架内提出了矮新星爆发的统一模型，其中两种不同的本征吸积盘内的不稳定性（即热不稳定性和潮汐不稳定性）起着至关重要的作用。在吸积盘两种内在不稳定性的不同稳定行为组合中，非磁激变变量在轨道周期与传质速率图中被分为四个区域，并且在该图中基本了解了它们不同的爆发行为。特别是，SU UMa型矮新星的爆发可以通过热潮汐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发挥着独特的作用。该周期以下的灾难性变星的丰富的爆发行为（即从“永久超级恒星”开始，到Z Cam类SU UMa星、“ER UMa星”，到普通SU UMa星，最后到WZ Sge星）通过热潮汐不稳定性模型来理解。

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。”

Osaki,Y.: "Dwarf nova outbursts : a unificatin theory" Lecture Notes in Physics No.487,Accretion Disks-New Aspects,eds.E.Meyer-Hofmeister et al.(Springer Verlag,Heidelberg,Berlin). 92-102 (1997)

Osaki,Y.：“矮新星爆发：统一理论”物理学讲义第 487 号，吸积盘-新方面，E.Meyer-Hofmeister 等人编着（Springer Verlag，海德堡，柏林）。

M.Tsugawa et al.: "Disk Instability Model for AM Canum Venaticorum Stars" Pub1.Astron.Soc.Japan. 49. 75-84 (1997)

M.Tsukawa 等人：“AM Canum Venaticorum 星的盘不稳定性模型”Pub1.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。