Nonlinear beat cepheid models

Z. Kolláth, J. P. Beaulieu, J. R. Buchler, P. Yecko

Research output: Contribution to journalArticle

34 Citations (Scopus)


The numerical hydrodynamic modeling of beat Cepheid behavior has been a long-standing quest in which purely radiative models have failed miserably. We find that beat pulsations occur naturally when turbulent convection is accounted for in our hydrodynamics codes. The development of a relaxation code and of a Floquet stability analysis greatly facilitates the search for and analysis of beat Cepheid models. The conditions for the occurrence of beat behavior can be understood easily and at a fundamental level with the help of amplitude equations. Here a discriminant D arises whose sign decides whether single-mode or double-mode pulsations can occur in a model, and this D depends only on the values of the nonlinear coupling coefficients between the fundamental and the first overtone modes. For radiative models D is always found to be negative, but with sufficiently strong turbulent convection its sign reverses.

Original languageEnglish
Pages (from-to)L55-L58
JournalAstrophysical Journal Letters
Issue number1
Publication statusPublished - Jul 20 1998


  • Cepheids
  • Convection
  • Hydrodynamics
  • Magellanic Clouds
  • Stars: oscillations
  • Turbulence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Kolláth, Z., Beaulieu, J. P., Buchler, J. R., & Yecko, P. (1998). Nonlinear beat cepheid models. Astrophysical Journal Letters, 502(1), L55-L58.