Mass Ratio q1.0: Previously Calculated Single Star Models

To construct a corotating binary configuration for stars of unequal mass based on previously computed single star models, you can use the ``setup2qr'' subroutine, which is called by setting the three letter code in sph.init to ``2qr''.

For such configurations, you will need to construct models of both stars separately. Note that we do not require the stars to have different masses, it is fine to run different models for stars with the same mass. It is also acceptable to use stars with different values of the entropic variable $A_i$, and this is actually required if you want to deviate from the polytropic mass-radius relation. It is REQUIRED, however, that the stars have the same value of the adiabatic index $\Gamma$, since this is treated by the code as a single scalar defined for all of the particles. For stars with different values of $\Gamma$, you will need to make it a vector within the common blocks, and carefully edit every occurrence of it in the code to reflect the change.

The particle positions and other important parameters are read in from files called ``pos.sph'' and ``pos2.sph'', which you will need to create. We have supplied the code to make executables called ``b2pos'' and ``b2pos2'', which will write these files for you. Based on responses to two questions, they will convert binary output files, in the form ``out012.sph'' (or any other 3-digit number) or ``restart.sph'' into the ASCII pos.sph and pos2.sph files, respectively. In fact, they only differ in the name of the file to which they write their data. For more on file I/O, please see Sec. 5.