Binary-star calculations using isochrones from MIST

The calculations and plots herein are based on the isochrone models produced by

• MESA Isochrones & Stellar Tracks

In particular, the isochrones calculated for v/vcrit = 0.0. In addition, I've chosen a particular subset of models:

• age is exactly 1 Gyr
• star is still on (or nearly on) the main sequence

The second condition limits the calculations to models with indices between 0 and 458 in the isochrone file.

I read the information on models in this subset, with masses ranging from 0.1 to 2.0454 solar masses. For each model in the subset, I did the following:

1. chose a companion star from the subset
2. computed the absolute magnitude in B and V for the combined light of the two stars
3. computed the combined (B-V) color of the two stars

I printed one line of information for each pair of stars, in the following format:

# index mass_A  Tem_A  MB_A   MV_A    index mass_B  Tem_B  MB_B   MV_B    tot_MB tot_MV  tot_B-V
  193   0.1000   2886 17.444 15.817   193   0.1000   2886 17.444 15.817   16.691 15.065  1.627 
  193   0.1000   2886 17.444 15.817   194   0.1007   2889 17.412 15.789   16.676 15.050  1.625 
  193   0.1000   2886 17.444 15.817   195   0.1057   2912 17.174 15.569   16.548 14.934  1.614 

The entire output file can be downloaded:

• download ASCII text file

Below are several plots showing the selected aspects of the combined light of pairs of stars.

The combined B-band absolute magnitude of the two stars.

The combined V-band absolute magnitude of the two stars.

The combined (B-V) color of the two stars.