galpy.orbit.Orbit.V

Orbit.V(*args, **kwargs)

NAME:

V

PURPOSE:

return Heliocentric Galactic rectangular y-velocity (aka “V”)

INPUT:

t - (optional) time at which to get V (can be Quantity)

obs=[X,Y,Z,vx,vy,vz] - (optional) position and velocity of observer

in the Galactocentric frame (in kpc and km/s) (default=[8.0,0.,0.,0.,220.,0.]; entries can be Quantity) OR Orbit object that corresponds to the orbit of the observer Y is ignored and always assumed to be zero

ro= (Object-wide default) physical scale for distances to use to convert (can be Quantity)

vo= (Object-wide default) physical scale for velocities to use to convert (can be Quantity)

OUTPUT:

V(t) in km/s

HISTORY:

2011-02-24 - Written - Bovy (NYU)