The Relative Stability against Merger of Close, Compact Binaries

摘要

The orbital separation of compact binary stars will shrink with time owing to the emission of gravitational radiation. This inspiral phase of a binary system's evolution generally will be very long compared to the system's orbital period, but the final coalescence may be dynamical and driven to a large degree by hydrodynamic effects, particularly if there is a critical separation at which the system becomes dynamically unstable toward merger. Indeed, if weakly relativistic systems (such as white dwarf white dwarf binaries) encounter a point of dynamical instability at some critically close separation, coalescence may be entirely a classical, hydrodynamic process. Therefore, a proper investigation of this stage of binary evolution must include three-dimensional hydrodynamic simulations.