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- c*************************************************************************
- c ANAL_JACOBI.F
- c*************************************************************************
- c Calculates the Jacobi integral of a particle given the position and velocity
- c and ang. velocity vector of the Sun and Planet
- c
- c Input:
- c msun ==> Mass of the Sun (real scalar)
- c mpl ==> Mass of the Planet (real scalar)
- c omegax,..y,z ==> vector components of planet-sun orbit's
- c angular velocity vector(real scalars)
- c xb,yb,zb ==> Barycentric position of particle
- c (real scalars)
- c vxb,vyb,vzb ==> Barycentric vel of particle (real scalars)
- c xsb,ysb,zsb ==> Barycentric position of Sun (real scalars)
- c xplb,yplb,zplb ==> Barycentric position of planet (real scalars)
- c
- c Output:
- c jacobi ==> Value of the jacobi constant
- c
- c Remarks:
- c Authors: Martin Duncan
- c Date: April 13/93
- c Last revision: 3/4/93 HFL
- subroutine anal_jacobi(msun,mpl,omegax,omegay,omegaz,xb,yb,zb,
- & vxb,vyb,vzb,xsb,ysb,zsb,xplb,yplb,zplb,jacobi)
- include '../swift.inc'
- c... Inputs:
- real*8 msun,mpl,omegax,omegay,omegaz,xb,yb,zb,vxb,vyb,vzb
- real*8 xsb,ysb,zsb,xplb,yplb,zplb
- c... Outputs:
- real*8 jacobi
- c... Internals
- real*8 rr,jx,jy,jz
- c----
- c... Executable code
- jacobi = 0.5d0*(vxb**2 + vyb**2 + vzb**2)
- rr = sqrt((xb-xsb)**2 + (yb-ysb)**2 + (zb-zsb)**2)
- jacobi = jacobi - msun/rr
- rr = sqrt((xb-xplb)**2 + (yb-yplb)**2 + (zb-zplb)**2)
- jacobi = jacobi - mpl/rr
- jx = yb*vzb - zb*vyb
- jy = zb*vxb - xb*vzb
- jz = xb*vyb - yb*vxb
- jacobi = jacobi - omegax*jx - omegay*jy - omegaz*jz
- return
- end ! anal_jacobi
- c-------------------------------------------------------------------------
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