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Name

mkorbit - make an orbit with initial conditions

Synopsis

mkorbit out=orbit [parameter=value]

Description

mkorbit will generate an orbit by either given it the exact inititial coordinates in phase space, or specifying an energy and leaving out one of the velocities (the standard way to generate initial conditions for a surface of section plot). In the last case an external potential needs to be given.

Orbits can also be created from snapshots, by using stoo(1NEMO) .

Note: currently the z,vz coordinates are set to zero, generating effectively 2D orbits.

Parameters

The following parameters are recognized in any order if the keyword is also given:
out=out-file
output file, will be in orbit(5NEMO) format [no default]
x=x-position
Initial value of position along x-axis [default: not used]
y=y-position
Initial value of position along y-axis [default: not used]
vx=x-velocity
Initial value of velocity along x-axis [default: not used]
vy=y-velocity
Initial value of velocity along y-axis [default: not used]
etot=energy
Energy of the orbit. If no value is given, the program assumes that all phase space coordinates will be used. If a value for the energy is given, one of the phase space velocities may be left out, and will be calculated. In this case the potential where the orbit is calculated in, must also be given, see next 3 parameters [default: not used].
lz=
The sign of lz will determine sense of rotation if only X or Y is given with etot.
potname=name
name of file of the potential(5NEMO) descriptor, in case it is needed [default: none].
potpars=par-list
List of parameters to the potential descriptor. The first parameter MUST be the pattern speed in the x-y plane, (although rotating frames of reference are not supported in all programs). The remaining parameters are used by the inipotential() routine in the potential descriptor. [default: none - let them be defined by routine itself].
potfile=name
name of an optional datafile to the potential descriptor. This might be an N-body snapshot or table of spline fit coefficients etc. [default: none].

Examples

To fully specify an orbit without the need for a potential
  % mkorbit orb1.dat 1 0 0  0 1 0
one can specifiy a potential, which simplifies using it in orbint(1NEMO) as the potential parameters do not need to be specified again:
  % mkorbit orb2.dat 1 0 0  0 1 0 potname=plummer potpars=0,2.0,0.3
or specify a launch point on the X or Y axis, and an energy, but here the potential is required:
  % mkorbit orb3.dat x=1 e=-1.4 potname=plummer potpars=0,2.0,0.3

See Also

stoo(1NEMO) , potlist(1NEMO) , orblist(1NEMO) , mkgalorbit(1NEMO) , mk2body(1NEMO) , potential(5NEMO)

Author

Peter Teuben

Files


~/src/orbit/io      mkorbit.c

Update History


xx-jul-87    V1.0: Created:    PJT
4-May-88    V2.1: keywords e,potential etc. implemented    PJT
2-Jun-88    V2.2: new filestruct, no code change    PJT
2-Mar-92    V2.3: new NEMO 2.x    PJT
10-dec-2019    V4.4: implemented PHI/ACC storage; simplified orbit launching    PJT


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