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Review of Cataclysmic Variables : Unification model for various types of variations Makoto Uemura (Kyoto University : VSNET team)

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Presentation on theme: "Review of Cataclysmic Variables : Unification model for various types of variations Makoto Uemura (Kyoto University : VSNET team)"— Presentation transcript:

1 Review of Cataclysmic Variables : Unification model for various types of variations Makoto Uemura (Kyoto University : VSNET team)

2 Contents Recent works of the VSNET team Recent works of the VSNET team Various types of variations in CVs Various types of variations in CVs Unification model for the CV activity Unification model for the CV activity To see accretion disks To see accretion disks Summary Summary

3 Recent works 1 : GRB Left : CCD images of GRB taken at Kyoto University (Rc=19.3). The right image is from DSS.

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8 Black hole X-ray transient V4641 Sgr

9 WZ Sge outburst in 2001 (VSNET)

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11 Sub-groups of CVs Nova Nova Dwarf nova Dwarf nova SS Cyg SS Cyg Z Cam Z Cam SU UMa SU UMa WZ Sge WZ Sge Nova-like variables RW Tri UX UMa SW Sex VY Scl Magnetic CVs Polar Intermediate polar

12 Dwarf nova U Gem 6mag 1yr Outburst (VSNET)

13 Dwarf nova Z Cam 3ma g 3mon Standstill (VSNET)

14 Dwarf nova SU UMa 3ma g 1mon Normal outburst Superoutburst (VSNET)

15 Superhumps in SU UMa stars (VSNET)

16 Nova-like variable UX UMa 2mag 1yr (VSNET)

17 Characteristics of sub-classes SS Cyg : (normal) outburst SS Cyg : (normal) outburst Z Cam : standstill Z Cam : standstill SU UMa : superoutburst + superhumps SU UMa : superoutburst + superhumps Nova-like variables : quasi-steady Nova-like variables : quasi-steady

18 Artist s view of CVs (Credit: K. Smale)

19 P orb – Mv relation Dwarf nova Novalike Z Cam SS Cyg SU UMa (Warner 1987)

20 Unification model of CVs : 1. Thermal instability of accretion disk Low temperature Quiescence High temperature Outburst

21 Unification model of CVs : 2. Tidal instability model P superhump ~ 1.03 P orbital (SPH simulation by Murray)

22 P orb – Mv relation Dwarf nova Novalike Z Cam SS Cyg SU UMa Thermal instability Tidal instability (Osaki 1996)

23 Observation of disks Observation of disks Observation Eclipse mapping

24 Examples of eclipse mapping: IY UMa Superoutburst on 2000 January Early phase with fully- grown superhumps Late phase with late superhumps

25 Examples of eclipse mapping: DV UMa Superoutburst on 1999 December Rapid evolution of an accretion disk during the very early phase of the superoutburst Rapid evolution of an accretion disk during the very early phase of the superoutburst

26 Summary Various types of variations in CVs can basically be interpreted with two instabilities within accretion disks. Various types of variations in CVs can basically be interpreted with two instabilities within accretion disks. The eclipse mapping method is a strong tool to study accretion disks. For investigation of continuous evolution of disks, multi- longitude observations are essential. The eclipse mapping method is a strong tool to study accretion disks. For investigation of continuous evolution of disks, multi- longitude observations are essential. VSNET serves a number of information on variable stars through s, ftp, and web. Let s enjoy the world of VSNET ! (http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/index.html) VSNET serves a number of information on variable stars through s, ftp, and web. Let s enjoy the world of VSNET ! (http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/index.html)


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