helium_star.h

/*
 * helium_star.h: derived class for evolution of naked helium core
 *                burning stars.
 *
 *.....................................................................
 *    version 1:  Jan 1994   Simon F. Portegies Zwart
 *    version 2:
 *...................................................................
 *     This file includes:
 *  1) definition of class helium_star
 *
 *....................................................................
 */

#ifndef    _HELIUM_STAR 
#   define _HELIUM_STAR

#include "single_star.h"
#include "white_dwarf.h"
#include "helium_giant.h"

class         main_sequence;
class         hyper_giant;
class         hertzsprung_gap;
class         sub_giant;
class         horizontal_branch;

/*-----------------------------------------------------------------------------
 *  helium_star  --  a derived class for element evolution.
 *-----------------------------------------------------------------------------
 */
class helium_star : public single_star {
      private :

        real final_core_mass;

        real CO_core_mass();
      
      public :

         helium_star(main_sequence &);
         helium_star(hyper_giant &);
         helium_star(hertzsprung_gap &);
         helium_star(sub_giant &);
         helium_star(horizontal_branch &);
         helium_star(node* n) : single_star(n) {
           final_core_mass=-1;
         }

         ~helium_star() {}

         bool star_with_COcore() {return true;}   

         stellar_type get_element_type();

         void adjust_next_update_age(); 
         void instantaneous_element();
         void evolve_element(const real);
         void update();
         void stellar_wind(const real);
         void update_wind_constant();
         void create_remnant();
         bool hydrogen_envelope_star() {return false;}
         real temperature();
         
//              Mass transfer utilities.
         real accretion_limit(const real, const real);
         star* subtrac_mass_from_donor(const real, real&);
         star* reduce_mass(const real);
         real add_mass_to_accretor(const real);
         real add_mass_to_accretor(real, const real);
         void adjust_accretor_age(const real, const bool=true);

//              Stability rourines.
        real zeta_adiabatic();
        real zeta_thermal();
        real gyration_radius_sq();

        // not private because of super_giant::initial_CO_core_mass()
        real final_CO_core_mass(const real initial_mass);
        
        friend helium_giant::helium_giant(helium_star &);
        friend white_dwarf::white_dwarf(helium_star &);
   };
#endif          // _HELIUM_STAR

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