Line data    Source code

       1              : #ifndef __mx_astro_blackbody_hpp__
       2              : #define __mx_astro_blackbody_hpp__
       3              : 
       4              : #include <vector>
       5              : 
       6              : #include "units.hpp"
       7              : #include "constants.hpp"
       8              : #include "../math/constants.hpp"
       9              : 
      10              : namespace mx
      11              : {
      12              : namespace astro
      13              : {
      14              : 
      15              : template <typename units>
      16              : typename units::realT equilibriumTemp( typename units::realT L,  ///< [in] Stellar luminosity
      17              :                                        typename units::realT r,  ///< [in] Distance from star
      18              :                                        typename units::realT Ab, ///< [in] Bond Albedo
      19              :                                        typename units::realT f   ///< [in] Redistribution factor
      20              : )
      21              : {
      22              :     typedef typename units::realT realT;
      23              : 
      24              :     return pow( ( L * ( 1 - Ab ) / f ) /
      25              :                     ( static_cast<realT>( 16.0 ) * constants::sigma<units>() * math::pi<realT>() * r * r ),
      26              :                 static_cast<realT>( 0.25 ) );
      27              : }
      28              : 
      29              : /// The blackbody spectral energy distribution in the mx::astro::astroSpectrum form.
      30              : /** You specify the temperature, and optionally the radius and distance of the blackbody.
      31              :  *
      32              :  * \tparam units specifies the units of the spectrum
      33              :  * \tparam freq if true, then the blackbody is calcuated as a frequency distribution.  If false (default), it is a
      34              :  * wavelength distribution.
      35              :  */
      36              : template <typename units, bool freq = false>
      37              : struct blackbody
      38              : {
      39              :     typedef typename units::realT realT; ///< The real floating point type used for calculations
      40              : 
      41              :     realT _temperature; ///< The temperature of the blackbody.  Default value is the effective temperature of the Sun.
      42              :     realT _radius;      ///< The optional radius of the blackbody.
      43              :     realT _distance;    ///< The optional distance to the blackbody.
      44              : 
      45              :     std::vector<realT> _spectrum; ///< The calculated spectral energy distribution.
      46              : 
      47              :     /// Default c'tor.
      48            0 :     blackbody()
      49            0 :     {
      50            0 :         _temperature = constants::TeffSun<units>();
      51            0 :         _radius = 0;
      52            0 :         _distance = 0;
      53            0 :     }
      54              : 
      55              :     /// Constructor used to initialize parameters.
      56            0 :     blackbody(
      57              :         realT
      58              :             T, ///< [in] The effective temperature of the blackbody. Units as specified by the units template-parameter.
      59              :         realT R =
      60              :             0, ///< [in] [optional] The radius of the blackbody. Units as specified by the units template-parameter.
      61              :         realT d =
      62              :             0 ///< [in]  [optional] The distance to the blackbody. Units as specified by the units template-parameter.
      63              :     )
      64            0 :     {
      65            0 :         setParameters( T, R, d );
      66            0 :     }
      67              : 
      68              :     /// Set the parameters of the blackbody.
      69            0 :     void setParameters(
      70              :         realT
      71              :             T, ///< [in] The effective temperature of the blackbody. Units as specified by the units template-parameter.
      72              :         realT R, ///< [in] The radius of the blackbody. Units as specified by the units template-parameter.
      73              :         realT d  ///< [in] The distance to the blackbody. Units as specified by the units template-parameter.
      74              :     )
      75              :     {
      76            0 :         _temperature = T;
      77            0 :         _radius = R;
      78            0 :         _distance = d;
      79            0 :     }
      80              : 
      81              :     template <typename gridT>
      82              :     int setSpectrum( gridT &grid )
      83              :     {
      84              :         constexpr realT h = constants::h<units>();
      85              :         constexpr realT c = constants::c<units>();
      86              :         constexpr realT k = constants::k<units>();
      87              : 
      88              :         realT solidang = 1.0;
      89              : 
      90              :         if( _radius != 0 and _distance != 0 )
      91              :         {
      92              :             solidang = math::pi<realT>() * pow( _radius / _distance, 2 );
      93              :         }
      94              : 
      95              :         _spectrum.resize( grid.size() );
      96              : 
      97              :         for( int i = 0; i < grid.size(); ++i )
      98              :         {
      99              :             if( !freq )
     100              :             {
     101              :                 _spectrum[i] =
     102              :                     2 * h * pow( c, 2 ) * solidang / pow( grid[i], 5 ) /
     103              :                     expm1( h * c / ( grid[i] * k * _temperature ) ); // (exp(h*c/(grid[i]*k*_temperature))-1.0);
     104              :             }
     105              :             else
     106              :             {
     107              :                 _spectrum[i] =
     108              :                     2 * h / pow( c, 2 ) * solidang * pow( grid[i], 3 ) /
     109              :                     expm1( exp( h * grid[i] / ( k * _temperature ) ) ); // (exp(h*grid[i]/(k*_temperature))-1.0);
     110              :             }
     111              :         }
     112              :         return 0;
     113              :     }
     114              : 
     115            0 :     realT operator[]( int i )
     116              :     {
     117            0 :         return _spectrum[i];
     118              :     }
     119              : };
     120              : 
     121              : } // namespace astro
     122              : } // namespace mx
     123              : #endif //__mx_astro_blackbody_hpp__