Interacting binaries with eccentric orbits: Secular orbital evolution due to conservative mass transfer

J. F. Sepinsky*, B. Willems, V. Kalogera, F. A. Rasio

*Corresponding author for this work

Research output: Contribution to journalArticle

52 Scopus citations

Abstract

We investigate the secular evolution of the orbital semimajor axis and eccentricity due to mass transfer in eccentric binaries, assuming conservation of total system mass and orbital angular momentum. Assuming a delta function mass transfer rate centered at periastron, we find rates of secular change of the orbital semimajor axis and eccentricity which are linearly proportional to the magnitude of the mass transfer rate at periastron. The rates can be positive as well as negative, so that the semimajor axis and eccentricity can increase as well as decrease in time. Adopting a delta function mass-transfer rate of 10-9 M yr-1 at periastron yields orbital evolution timescales ranging from a few Myr to a Hubble time or more, depending on the binary mass ratio and orbital eccentricity. Comparison with orbital evolution timescales due to dissipative tides furthermore shows that tides cannot, in all cases, circularize the orbit rapidly enough to justify the often-adopted assumption of instantaneous circularization at the onset of mass transfer. The formalism presented can be incorporated in binary evolution and population synthesis codes to create a self-consistent treatment of mass transfer in eccentric binaries.

Original languageEnglish (US)
Pages (from-to)1170-1184
Number of pages15
JournalAstrophysical Journal
Volume667
Issue number2 I
DOIs
StatePublished - 2007

Keywords

  • Binaries: close
  • Celestial mechanics
  • Stars: mass loss

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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