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Cataclysmic Variables

Cataclysmic Variables

Course Outline: 

Interacting Binary stars are double stars that transfer mass from one component to the other. Often the transfer creates an accretion disc around the accreting star. In most of the interesting interacting binaries the accretor is degenerate - i.e. a white dwarf, a neutron star, or a black hole. Accretion discs also occur in the early stages of star formation, and around black holes in the centres of galaxies. This course will look at the physical mechanisms that are important in the class of interacting binaries known as Cataclysmic Variable Stars, which include the Novae.


Basic Structure of Interacting Binaries

  • White Dwarfs.
  • Roche Geometry.
  • Mass Transfer.
  • Phometric Properties.

Spectral Characteristics

  • Spectra of the white dwarf, the donor star and the accretion disc.

Evolution of Cataclysmic Variables

  • Common envelope.
  • Period Distribution.
  • Magnetic Braking and angular momentum loss.

Accretion Discs

  • Dwarf Nova outbursts.
  • Thermal and tidal Instabilities.
  • Superoutburst and superhumps.

Boundary Layers and Winds

  • The Disc-Star boundary.
  • Winds from Discs.
  • Stream impact.

Magnetic Cataclysmic Variables

  • Stream accretion.
  • Polars.
  • Cyclotron emission.
  • Intermediate Polars.
  • Propellers.
  • Dwarf Nova Oscillations.
  • Quasi-Periodic Oscillations.

Nova Eruptions

  • Thermonuclear runaway.
  • Recurrent novae.
  • Supersoft X-Ray Sources.


  • Cataclysmic Variable Stars: How and Why they Vary. C. Hellier, Springer-Praxis, 2001
  • Cataclysmic Variable Stars. B. Warner. Cambridge University Press, 1995

Programmes | by Dr. Radut