LORENE
bin_bhns_extr_omegaana.C
1 /*
2  * Methods of class Bin_bhns_extr to set analytical value to omega
3  *
4  * (see file bin_bhns_extr.h for documentation).
5  *
6  */
7 
8 /*
9  * Copyright (c) 2004 Keisuke Taniguchi
10  *
11  * This file is part of LORENE.
12  *
13  * LORENE is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License version 2
15  * as published by the Free Software Foundation.
16  *
17  * LORENE is distributed in the hope that it will be useful,
18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20  * GNU General Public License for more details.
21  *
22  * You should have received a copy of the GNU General Public License
23  * along with LORENE; if not, write to the Free Software
24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25  *
26  */
27 
28 
29 
30 /*
31  * $Id: bin_bhns_extr_omegaana.C,v 1.4 2016/12/05 16:17:46 j_novak Exp $
32  * $Log: bin_bhns_extr_omegaana.C,v $
33  * Revision 1.4 2016/12/05 16:17:46 j_novak
34  * Suppression of some global variables (file names, loch, ...) to prevent redefinitions
35  *
36  * Revision 1.3 2014/10/13 08:52:42 j_novak
37  * Lorene classes and functions now belong to the namespace Lorene.
38  *
39  * Revision 1.2 2014/10/06 15:13:00 j_novak
40  * Modified #include directives to use c++ syntax.
41  *
42  * Revision 1.1 2004/11/30 20:46:36 k_taniguchi
43  * *** empty log message ***
44  *
45  *
46  * $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 $
47  *
48  */
49 
50 // C headers
51 #include <cmath>
52 
53 // Lorene headers
54 #include "bin_bhns_extr.h"
55 #include "unites.h"
56 
57 namespace Lorene {
59 
60  using namespace Unites ;
61 
62  // BH-NS binary systems should be relativistic
63  // -------------------------------------------
64  if ( !star.is_relativistic() ) {
65 
66  cout << "BH-NS binary systems should be relativistic !!!" << endl ;
67  abort() ;
68  }
69 
70  double rr = separ ;
71  double mtot = mass_bh ; // Approximates the extreme mass ratio
72 
73  // Compaction factor
74  double compact = ggrav * mtot / rr ;
75 
76  double omega2 ;
77 
78  if ( star.is_irrotational() ) {
79 
80  // Irrotational case
81  // -----------------
82 
83  omega2 = ggrav * mtot / pow(rr, 3.)
84  * (1. - 2.75 * compact + 8.625 * compact*compact ) ;
85 
86  }
87  else {
88  // Corotating case
89  // ---------------
90 
91  // a0/R
92  double a0sr = star.ray_eq() / rr ;
93 
94  // Rescaled moment of inertia 5 I / (2 M a0^2)
95  double ired = double(5)/double(3) * ( 1. - double(6)/M_PI/M_PI ) ;
96  omega2 = ggrav * mtot / pow(rr, 3.)
97  * (1. - compact * ( 2.75 + 2.*a0sr*a0sr * ired
98  - 0.48*pow(a0sr, 4) * ired*ired )
99  + compact*compact * ( 8.625 + 2.75*a0sr*a0sr * ired
100  + 2.*pow(a0sr, 4) * ired*ired ) ) ;
101 
102  }
103 
104  omega = sqrt( omega2 ) ;
105 
106  // The derived quantities are obsolete:
107  del_deriv() ;
108 
109 }
110 }
Cmp sqrt(const Cmp &)
Square root.
Definition: cmp_math.C:223
Lorene prototypes.
Definition: app_hor.h:67
Standard units of space, time and mass.
double ray_eq() const
Coordinate radius at , [r_unit].
bool is_irrotational() const
Returns true for an irrotational motion, false for a corotating one.
Definition: etoile.h:1095
Et_bin_bhns_extr star
Neutron star.
Definition: bin_bhns_extr.h:66
void del_deriv() const
Deletes all the derived quantities.
Cmp pow(const Cmp &, int)
Power .
Definition: cmp_math.C:351
double separ
Absolute orbital separation between two centers of BH and NS.
Definition: bin_bhns_extr.h:74
double omega
Angular velocity with respect to an asymptotically inertial observer.
Definition: bin_bhns_extr.h:71
void analytical_omega()
Sets the orbital angular velocity to some 2-PN analytical value (Keplerian value in the Newtonian cas...
bool is_relativistic() const
Returns true for a relativistic star, false for a Newtonian one.
Definition: etoile.h:670
double mass_bh
Gravitational mass of BH.
Definition: bin_bhns_extr.h:77