Abstract
For over a decade, comparisons of high resolution line profiles with simple, 3/2-D bow shock models have been used to derive the general properties of Herbig-Haro (HH) objects. In particular, the parameters which have been derived are the bow shock velocity, the direction of motion of the object, and the motion of the environment into which the object is moving. This paper presents an analysis of how to derive these parameters from observations of proper motions of the condensations of a HH object. Simple expressions are derived for determining the relevant parameters from measurements of the components of the proper motion velocities along and perpendicular to the projected outflow axis. These prescriptions are then applied to the observed proper motions of HH 1, HH 32 and HH 34, for which we obtain the respective flow parameters.
