Effect of the coriolis force on the hydrodynamics of colliding-wind binaries

M. Nicole Lemaster, James McLellan Stone, Thomas A. Gardiner

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

Using fully three-dimensional hydrodynamic simulations, we investigate the effect of the Coriolis force on the hydrodynamic and observable properties of colliding-wind binary systems. To make the calculations tractable, we assume adiabatic, constant velocity winds. The neglect of radiative driving, gravitational deceleration, and cooling limits the application of our models to real systems. However, these assumptions allow us to isolate the effect of the Coriolis force, and by simplifying the calculations, allow us to use a higher resolution (up to 6403) and to conduct a larger survey of parameter space. We study the dynamics of colliding winds with equal mass-loss rates and velocities emanating from equal-mass stars on circular orbits, with a range of values for the ratio of the wind to orbital velocity. We also study the dynamics of winds from stars on elliptical orbits and with unequal-strength winds. Orbital motion of the stars sweeps the shocked wind gas into an Archimedean spiral with asymmetric shock strengths and therefore unequal postshock temperatures and densities in the leading and trailing edges of the spiral. We observe the Kelvin-Helmholtz instability at the contact surface between the shocked winds in systems with orbital motion even when the winds are identical. The change in shock strengths caused by orbital motion increases the volume of X-ray emitting postshock gas with T > 0.59 keV by 63%, for a typical system, as the ratio of wind velocity to orbital velocity decreases to V w/Vo = 2.5. This causes increased free-free emission from systems with shorter orbital periods and an altered time dependence of the wind attenuation. We comment on the importance of the effects of orbital motion on the observable properties of colliding-wind binaries.

Original languageEnglish (US)
Pages (from-to)582-595
Number of pages14
JournalAstrophysical Journal
Volume662
Issue number1 I
DOIs
StatePublished - Jun 10 2007

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Binaries: general
  • Hydrodynamics
  • Stars: Wolf-Rayet
  • Stars: early-type
  • Stars: winds, outflows
  • X-rays: stars

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