inclin.f

Go to the documentation of this file.

      SUBROUTINE inclin(X,V,XCM,VCM,ALPHA)
*
*
*       Inclination of hierarchical system.
*       -----------------------------------
*
      REAL*8  a12,a22,a1a2,fac,alpha
      REAL*8  xcm(3),vcm(3),x(3,3),v(3,3),a0(3),a2(3)
*
*
*       Define inner binary I1 & I2 and outer component I3.
      i1 = 1
      i2 = 2
      i3 = 3
*
*       Evaluate scalar products of angular momenta.
      a12 = 0.0
      a22 = 0.0
      a1a2 = 0.0
      DO 20 k = 1,3
          k1 = k + 1
          IF (k1.GT.3) k1 = 1
          k2 = k1 + 1
          IF (k2.GT.3) k2 = 1
          a0(k) = (x(k1,i1) - x(k1,i2))*(v(k2,i1) - v(k2,i2))
     &          - (x(k2,i1) - x(k2,i2))*(v(k1,i1) - v(k1,i2))
          a2(k) = (x(k1,i3) - xcm(k1))*(v(k2,i3) - vcm(k2))
     &          - (x(k2,i3) - xcm(k2))*(v(k1,i3) - vcm(k1))
          a12 = a12 + a0(k)**2
          a22 = a22 + a2(k)**2
          a1a2 = a1a2 + a0(k)*a2(k)
   20 CONTINUE
*
*       Determine inclination in radians.
      fac = a1a2/sqrt(a12*a22)
      fac = min(fac,1.0d0)
      alpha = acos(fac)
*
      RETURN
*
      END