Potential.rtide(R, z, phi=0.0, t=0.0, M=None)[source]

Calculate the tidal radius for object of mass M assuming a circular orbit

  • R (float or Quantity) – Galactocentric radius

  • z (float or Quantity) – height

  • phi (float or Quantity, optional) – azimuth (default: 0.0)

  • t (float or Quantity, optional) – time (default: 0.0)

  • M (float or Quantity) – mass of the object


Tidal radius

Return type:

float or Quantity


  • 2018-03-21 - Written - Webb (UofT)

  • The tidal radius is computed as

    \[r_t^3 = \frac{GM_s}{\Omega^2-\mathrm{d}^2\Phi/\mathrm{d}r^2}\]

    where \(M_s\) is the cluster mass, \(\Omega\) is the circular frequency, and \(\Phi\) is the gravitational potential. For non-spherical potentials, we evaluate \(\Omega^2 = (1/r)(\mathrm{d}\Phi/\mathrm{d}r)\) and evaluate the derivatives at the given position of the cluster.