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Review of C ataclysmic Variables : Unification model for various types of variations

Review of C ataclysmic Variables : Unification model for various types of variations. Makoto Uemura (Kyoto University : VSNET team). Contents. Recent works of the VSNET team Various types of variations in CVs Unification model for the CV activity To “ see ” accretion disks Summary.

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Review of C ataclysmic Variables : Unification model for various types of variations

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  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 • Various types of variations in CVs • Unification model for the CV activity • To “see” accretion disks • Summary

  3. Recent works 1 : GRB 010222 Left : CCD images of GRB 010222 taken at Kyoto University (Rc=19.3). The right image is from DSS.

  4. Black hole X-ray transient V4641 Sgr

  5. WZ Sge outburst in 2001 (VSNET)

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

  7. Dwarf nova U Gem 1yr “Outburst” 6mag (VSNET)

  8. Dwarf nova Z Cam 3mon “Standstill” 3mag (VSNET)

  9. Dwarf nova SU UMa 1mon “Superoutburst” Normal outburst 3mag (VSNET)

  10. Superhumps in SU UMa stars (VSNET)

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

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

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

  14. Porb – Mv relation Novalike Z Cam SS Cyg SU UMa Dwarf nova (Warner 1987)

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

  16. Unification model of CVs :2. Tidal instability model Psuperhump ~ 1.03 Porbital (SPH simulation by Murray)

  17. Porb – Mv relation Novalike Tidal instability Z Cam Thermal instability SS Cyg SU UMa Dwarf nova (Osaki 1996)

  18. Observation of “disks” Observation Eclipse mapping

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

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

  21. Summary • 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. • VSNET serves a number of information on variable stars through e-mails, ftp, and web. Let’s enjoy the world of VSNET ! (http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/index.html)

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