SNAPBINARY(1NEMO) manual page

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snapbinary - analyze binaries in a snapshot

For a given pair of stars, some statistics is computed of what kind of binary it is (ignoring any other stars in the neighborhood). For a bound pair the semi-major axis, period and eccentricity will be given.

The program snapstat(1NEMO) with option debug=1 will report the progression of nearest neighbors, which are good candidates for binaries.

Parameters

The following parameters are recognized in any order if the keyword is also given:

in=: input file name [???]
i1=: First star, where 0 is the first star in the snapshot. A nemoinp(1NEMO) list (e.g. 0:100) can also be given. [0]
i2=: Second star. A nemoinp(1NEMO) list (e.g. 0:100) can also be given, but only stars greater than i1= are used. [1]
bound=t|f: If given, only bound stars are listed. [t]
out=: Optional out with strongest bound pair sink’d.

Examples

In this given snapshot snapstat(1NEMO) is used to report close pairs (but note it will only report pairs closer than the previous one):

% snapstat snap22 exact=t all=t debug=1
### nemo Debug Info: rmin=31.0396 for (0,1) mass (0.00131882,0.000923836)
### nemo Debug Info: rmin=8.34925 for (0,4) mass (0.00131882,0.000368837)
### nemo Debug Info: rmin=5.88091 for (0,5) mass (0.00131882,0.000265256)
### nemo Debug Info: rmin=4.40751 for (0,6) mass (0.00131882,0.000296517)
### nemo Debug Info: rmin=2.86166 for (0,7) mass (0.00131882,0.000534057)
### nemo Debug Info: rmin=2.70097 for (0,28) mass (0.00131882,0.000926514)
### nemo Debug Info: rmin=0.315905 for (1,8) mass (0.000923836,0.00156653)
### nemo Debug Info: rmin=0.0229803 for (8,33) mass (0.00156653,0.000452991)
### nemo Debug Info: rmin=0.00713546 for (23,24) mass (0.000450885,0.000545665)
### nemo Debug Info: rmin=0.00623804 for (23,26) mass (0.000450885,0.000242503)
### nemo Debug Info: rmin=0.00586965 for (41,46) mass (0.0132193,0.0132209)
### nemo Debug Info: rmin=0.00439421 for (45,151) mass (0.00408217,0.00155427)
### nemo Debug Info: rmin=0.00404594 for (51,141) mass (0.00565297,0.00139231)
### nemo Debug Info: rmin=0.00345551 for (61,138) mass (0.00394162,0.00155196)
### nemo Debug Info: rmin=0.00337327 for (61,141) mass (0.00394162,0.00139231)
### nemo Debug Info: rmin=0.00292007 for (64,68) mass (0.00475124,0.00506128)
### nemo Debug Info: rmin=0.00240338 for (70,76) mass (0.00603871,0.0529179)
### nemo Debug Info: rmin=0.00133495 for (70,93) mass (0.00603871,0.0048034)
### nemo Debug Info: rmin=0.00097828 for (145,420) mass (0.00324217,0.00133839)
### nemo Debug Info: rmin=0.000652002 for (188,406) mass (0.00122891,0.000262444)
Star 70 might be part of a triple.
% snapbinary snap22  188 406
  m1,m2,mu: 0.00122891 0.000262444 0.00149135
  pos,vel:  0.000156675 -0.000590395 0.000228021 0.152756 -0.147408 0.406277
  T,W,E:    0.105062 -2.28734 -2.18228 
  H,|H|:    -0.000206252 -2.88217e-05 6.70914e-05 0.000218796
  a,b,p,e:  0.000341696 0.000104729 3.20995e-05 0.951871
  period:   0.00102766
  
% snapbinary snap22  1 8 bound=f
  m1,m2,mu: 0.000923836 0.00156653 0.00249036
  pos,vel:  0.29847 -0.0686271 -0.0774708 -0.113217 -0.010249 -0.0666479
  T,W,E:    0.00868257 -0.00788328 0.000799292 
  H,|H|:    0.00377985 0.0286634 -0.0108288 0.030873
  a,b,p,e:  -1.55786 -0.772167 0.382732 1.1161
  period:   Inf (Not a binary)

and here is an example with mk2body:

  % mk2body -  1 | snapbinary - 
  ### nemo Debug Info: U: -1   T: 0.25   T+U: -0.75  T/U: -0.25
  i1,i2:    0 1
  m1,m2,mu: 1 1 2
  pos,vel:  -1 0 0 0 -1 0
  T,W,E:    0.5 -2 -1.5 
  H,|H|:    0 0 1 1
  a,b,p,e:  0.666667 0.57735 0.5 0.5
  period:   2.4184

Files

NEMO/src/nbody/reduc/snapbinary.c

Author

Peter Teuben

Update History

3-Mar-2019    V0.1 quick hack        PJT
7-mar-2019    V0.3 i1= and i2= can be a list    PJT

Table of Contents

Name
Synopsis
Description
Parameters
Examples
See Also
Files
Author
Update History