bin_bhns_extr_omegaana.C

/*
 *  Methods of class Bin_bhns_extr to set analytical value to omega
 *
 *    (see file bin_bhns_extr.h for documentation).
 *
 */
 
/*
 *   Copyright (c) 2004 Keisuke Taniguchi
 *
 *   This file is part of LORENE.
 *
 *   LORENE is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License version 2
 *   as published by the Free Software Foundation.
 *
 *   LORENE is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with LORENE; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
 
 
 
/*
 * $Id: bin_bhns_extr_omegaana.C,v 1.4 2016/12/05 16:17:46 j_novak Exp $
 * $Log: bin_bhns_extr_omegaana.C,v $
 * Revision 1.4  2016/12/05 16:17:46  j_novak
 * Suppression of some global variables (file names, loch, ...) to prevent redefinitions
 *
 * Revision 1.3  2014/10/13 08:52:42  j_novak
 * Lorene classes and functions now belong to the namespace Lorene.
 *
 * Revision 1.2  2014/10/06 15:13:00  j_novak
 * Modified #include directives to use c++ syntax.
 *
 * Revision 1.1  2004/11/30 20:46:36  k_taniguchi
 * *** empty log message ***
 *
 *
 * $Header: /cvsroot/Lorene/C++/Source/Bin_bhns_extr/bin_bhns_extr_omegaana.C,v 1.4 2016/12/05 16:17:46 j_novak Exp $
 *
 */
 
// C headers
#include <cmath>
 
// Lorene headers
#include "bin_bhns_extr.h"
#include "unites.h"
 
namespace Lorene {
void Bin_bhns_extr::analytical_omega() {
 
  using namespace Unites ;
 
    // BH-NS binary systems should be relativistic
    // -------------------------------------------
    if ( !star.is_relativistic() ) {
 
        cout << "BH-NS binary systems should be relativistic !!!" << endl ;
        abort() ;
    }
 
    double rr = separ ;
    double mtot = mass_bh ; // Approximates the extreme mass ratio
 
    // Compaction factor
    double compact = ggrav * mtot / rr ;
 
    double omega2 ;
 
    if ( star.is_irrotational() ) {
 
        // Irrotational case
        // -----------------
 
        omega2 = ggrav * mtot / pow(rr, 3.)
      * (1. - 2.75 * compact + 8.625 * compact*compact ) ;
 
    }
    else {
        // Corotating case
        // ---------------
 
        // a0/R
        double a0sr = star.ray_eq() / rr ;
 
    // Rescaled moment of inertia 5 I / (2 M a0^2)
    double ired = double(5)/double(3) * ( 1. - double(6)/M_PI/M_PI ) ;
    omega2 = ggrav * mtot / pow(rr, 3.)
      * (1. - compact * ( 2.75 + 2.*a0sr*a0sr * ired
                  - 0.48*pow(a0sr, 4) * ired*ired )
         + compact*compact * ( 8.625 + 2.75*a0sr*a0sr * ired
                   + 2.*pow(a0sr, 4) * ired*ired ) ) ;
 
    }
 
    omega = sqrt( omega2 ) ;
 
    // The derived quantities are obsolete:
    del_deriv() ;
 
}
}