docs: def Trho_iddeg(rho,mu,mu_e):
      ''' 
      T(rho) that separates ideal gas and degenerate pressure dominated regions.
  
      Kippenhahn & Weigert, Eq. 16.6
  
      Parameters
      ----------
      rho : float
          Density array [cgs].
      mu : float
          Mean molecular weight.
      mu_e : float
          Mean molecular weight per free electron.
          
      '''
  
      T = 1.207E5 * rho**(old_div(2.,3.)) * mu / mu_e**(old_div(5.,3.))
      return T