Identification of moving groups and member selection usingHipparcosdata*

Abstract

A new method to identify coherent structures in velocity space — moving groups — in astrometric catalogues is presented: the Spaghetti method. It relies on positions, parallaxes and proper motions, and is ideally suited to searching for moving groups in the Hipparcos Catalogue. No radial-velocity information is required. The method has been tested extensively on synthetic data, and applied to the Hipparcos measurements for the Hyades and IC 2602 open clusters. The resulting lists of members agree very well with those of Perryman et al. for the Hyades and those of Whiteoak & Braes for IC 2602.