To create a range of masses of planets with inert cores, run the test case in star/test_suite/create_inert_core_planets

You can edit the inlist to determine details of the core -- find these lines and change them as desired:

      relax_core = .true.
      new_core_mass = 7.51105972250151d-5 ! 25 Mearth in Msun units
      ! these are just examples.  adjust them to values appropriate for your application.
         core_avg_rho = 10 ! g/cm^3
         core_avg_eps = 1d-6 ! ergs/g/sec








