Line data    Source code

       1              : ! ***********************************************************************
       2              : !
       3              : !   Copyright (C) 2010-2019  Meridith Joyce & The MESA Team
       4              : !
       5              : !   This program is free software: you can redistribute it and/or modify
       6              : !   it under the terms of the GNU Lesser General Public License
       7              : !   as published by the Free Software Foundation,
       8              : !   either version 3 of the License, or (at your option) any later version.
       9              : !
      10              : !   This program is distributed in the hope that it will be useful,
      11              : !   but WITHOUT ANY WARRANTY; without even the implied warranty of
      12              : !   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
      13              : !   See the GNU Lesser General Public License for more details.
      14              : !
      15              : !   You should have received a copy of the GNU Lesser General Public License
      16              : !   along with this program. If not, see <https://www.gnu.org/licenses/>.
      17              : !
      18              : ! ***********************************************************************
      19              : 
      20              : ! Module for handling starspot calculations
      21              : ! contains parameterized YREC routines
      22              : ! note: MESA models a pressure contrast rather than temperature contrast
      23              : 
      24              : module starspots
      25              : 
      26              :    use star_private_def
      27              :    use const_def, only: dp, pi4, boltz_sigma, cgas
      28              :    use utils_lib
      29              : 
      30              :    implicit none
      31              : 
      32              :    private
      33              :    public :: starspot_tweak_gradr
      34              :    public :: starspot_tweak_PT
      35              :    public :: starspot_restore_PT
      36              : 
      37              :    real(dp) :: L_init
      38              : 
      39              : contains
      40              : 
      41            0 :    subroutine starspot_tweak_gradr(s, P, gradr, gradr_spot)
      42              :       ! Purpose: adjusts the gradient of the radius to account for starspots.
      43              :       !
      44              :       ! This subroutine is called at the beginning of Get_results()
      45              :       ! in turb_support.f90
      46              : 
      47              :       use auto_diff_support
      48              :       type(star_info), pointer :: s
      49              :       type(auto_diff_real_star_order1), intent(in) :: P
      50              :       type(auto_diff_real_star_order1), intent(in) :: gradr
      51              :       type(auto_diff_real_star_order1), intent(out) :: gradr_spot
      52              : 
      53            0 :       real(dp) :: mu_ideal_gas, R2, Teff_local, PB_i
      54              :       type(auto_diff_real_star_order1) :: xspot_of_r  ! xspot4
      55              : 
      56            0 :       if (.not. s%doing_relax .and. .not. s%doing_first_model_of_run) then
      57            0 :          mu_ideal_gas = s%mu(1)  !1.00794d0 ! for hydrogen, 1 gram per mole
      58            0 :          R2 = pow2(s%R(1))
      59            0 :          Teff_local = pow(s%L(1)/(pi4*boltz_sigma*R2), 0.25d0)
      60            0 :          PB_i = (cgas*s%rho(1)/mu_ideal_gas)*(1.0d0 - s%xspot)*Teff_local
      61            0 :          xspot_of_r = (P - PB_i)/P
      62            0 :          gradr_spot = gradr/(s%fspot*pow4(xspot_of_r) + 1.0d0 - s%fspot)
      63              :       else
      64            0 :          gradr_spot = gradr
      65              :       end if
      66            0 :    end subroutine starspot_tweak_gradr
      67              : 
      68            0 :    subroutine starspot_tweak_PT(s)
      69              :       ! Purpose: saves the surface luminosity and adjusts it and the effective
      70              :       ! temperature to account for starspots.
      71              :       !
      72              :       ! This subroutine is called at the beginning of get_surf_PT()
      73              :       ! in hydro_vars.f90
      74              : 
      75              :       type(star_info), pointer :: s
      76              : 
      77            0 :       real(dp) :: alp
      78              : 
      79            0 :       alp = 1d0 - s%fspot + s%fspot*pow4(s%xspot)
      80              : 
      81              :       ! This is the surface-average value for luminosity
      82            0 :       L_init = s%L(1)
      83              : 
      84              :       ! Set the surface L to the unspotted, ambient L
      85            0 :       s%L(1) = s%L(1)/alp
      86              : 
      87              :       ! Now, set the Teff. Used in atm table lookup to set boundary conditions
      88            0 :       s%Teff = pow(s%L(1)/(pi4*pow2(s%r(1))*boltz_sigma), 0.25_dp)
      89              : 
      90            0 :    end subroutine starspot_tweak_PT
      91              : 
      92            0 :    subroutine starspot_restore_PT(s)
      93              :       ! Purpose: restores the surface luminosity and effective temperature.
      94              :       !
      95              :       ! Called at the end of get_surf_PT()
      96              : 
      97              :       type(star_info), pointer :: s
      98              : 
      99            0 :       s%Teff = pow(L_init/(pi4*pow2(s%r(1))*boltz_sigma), 0.25_dp)
     100            0 :       s%L(1) = L_init
     101              : 
     102            0 :    end subroutine starspot_restore_PT
     103              : 
     104              : end module starspots