Apex diagrams for the stellar population of the solar neighborhood

Abstract

We have studied some kinematic features of the coronas of near-solar stellar streams, based on Hipparcos observations. Apex diagrams for kinematic streams, open clusters, and field stars are plotted. In our analysis, we used the apex-diagram (AD) method we developed earlier. We find that the Eggen streams and Arcturus stream have similar properties, providing evidence for kinematic inhomogeneity of their coronas and the existence of stellar groups such as those detected in the corona of the Ursa Major stream.