horizontal_branch.h

/*
 * horizontal_branch.h: derived class for core-helium burning stars.
 *
 *.....................................................................
 *    version 1:    Jan 1994   Simon F. Portegies Zwart
 *    version 1.1:  Jan 1998   Simon F. Portegies Zwart
 *...................................................................
 *     This file includes:
 *  1) definition of class horizontal_branch
 *
 *....................................................................
 */

#ifndef    _HORIZONTAL_BRANCH 
#   define _HORIZONTAL_BRANCH

#include "single_star.h"
#include "super_giant.h"
#include "helium_star.h"

class hertzsprung_gap;
class sub_giant;
class single_star;

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

         horizontal_branch(sub_giant&);
         horizontal_branch(hertzsprung_gap&);
         horizontal_branch(node* n) : single_star(n) {}
         ~horizontal_branch() {}
         
         stellar_type get_element_type() {return Horizontal_Branch;}
         bool giant_star()             {return true;}
         bool star_with_COcore() {return true;}   

         void instantaneous_element();
         void evolve_element(const real);
         void evolve_core_mass(const real dt);

//            Mass transfer utilities.
        star* reduce_mass(const real);
        star* subtrac_mass_from_donor(const real, real&);
         void adjust_accretor_age(const real, const bool);
        void adjust_next_update_age();
        void update_wind_constant();
        void update();

//           Mass transfer stability
        real zeta_adiabatic();
        real zeta_thermal();
        real gyration_radius_sq();

//              Friend constructors
         friend super_giant::super_giant(horizontal_branch &);
         friend helium_star::helium_star(horizontal_branch &);
    };
#endif          // _HORIZONTAL_BRANCH

//        void adjust_initial_star();
//         real stellar_radius(const real, const real);

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