New Methods for Analyzing Proper Motion Fields
Abstract
Using h and chi Persei and the Trapezium in Orion as examples, a method is described for finding systematic structures in proper motion fields. Based on Strand's (1958) network around a reference point and average velocity vectors, Schnell (1968) refined this to identify contraction, expansion, and right and left rotation about that point. Using random number generators an accidental vector field is originated. Based on the frequency and quantity of individual motions, the statistical conditions necessary for the sketched analysis of vector fields to represent real, rather than accidental, structures are investigated. On the basis of 3823 vectors constructed by random number generators, it is calculated that if the quotients of statistically dimensionless numbers P, Q, and R (composed from the frequency of the components on both sides of a straight line, g, and a circle, c) are greater than 1.52, 1.30, and 1.21, respectively, then the structure is not accidental.
 Publication:

IAU Colloq. 48: Modern Astrometry
 Pub Date:
 1978
 Bibcode:
 1978moas.coll..371M
 Keywords:

 Astrometry;
 Astronomical Photography;
 Celestial Mechanics;
 Stellar Motions;
 Galactic Rotation;
 Stellar Rotation;
 Vector Analysis;
 Astronomy