Kukarkin-Parenago relationship

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The Kukarkin-Parenago relationship describes a linear relationship between the logarithm of the mean cycle length and the mean amplitude of eruptions of dwarf novae . The relationship is named after the two Russian first descriptors, Boris Wassiljewitsch Kukarkin and Pawel Petrovich Parenago .

From the Kukarkin-Parenago relationship it has been concluded that all dwarf novae, regardless of their subclass, have an identical breakout mechanism. Today this is described as a disk instability model, according to which the accretion disk in cataclysmic binary star systems is subject to a cyclical change in the viscosity parameter. If the internal friction assumes a high value, the accretion disc heats up and its luminosity increases by a factor of 10 to 1000. This is observed as a breakout, while with less internal friction the pane cools down and the brightness drops to a rest value.

Recurring novae also happen to follow the Kukarkin-Parenago relationship. Their breakout mechanism, however, is the explosive ignition of hydrogen burns on the surface of a white dwarf .

literature

  • Cuno Hoffmeister , G. Richter, W. Wenzel: Variable stars . JA Barth Verlag, Leipzig 1990, ISBN 3-335-00224-5 .
  • Iwona Kotko, Jean-Pierre Lasota: The viscosity parameter α and the properties of accretion disc outbursts in close binaries . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1209.0017 .