Hydrodynamics of rotating stars and close binary interactions: Compressible ellipsoid models

Dong Lai*, Frederic A. Rasio, Stuart L. Shapiro

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


We develop a new formalism to study the dynamics of fluid polytropes in three dimensions. The stars are modeled as compressible ellipsoids, and the hydrodynamic equations are reduced to a set of ordinary differential equations for the evolution of the principal axes and other global quantities. Both viscous dissipation and the gravitational radiation reaction are incorporated. We establish the validity of our approximations and demonstrate the simplicity and power of the method by rederiving a number of known results concerning the stability and dynamical oscillations of rapidly rotating polytropes. In particular, we present a generalization to compressible fluids of Chandrasekhar's classical results for the secular and dynamical instabilities of incompressible Maclaurin spheriods. We also present several applications of our method to astrophysical problems of great current interest, such as the tidal disruption of a star by a massive black hole, the coalescence of compact binaries driven by the emission of gravitational waves, and the development of instabilities in close binary systems.

Original languageEnglish (US)
Pages (from-to)742-769
Number of pages28
JournalAstrophysical Journal
Issue number2
StatePublished - Dec 20 1994


  • Binaries: close
  • Hydrodynamics
  • Instabilities
  • Stars: oscillations
  • Stars: rotation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Hydrodynamics of rotating stars and close binary interactions: Compressible ellipsoid models'. Together they form a unique fingerprint.

Cite this