Binary Clusters: Theory and Observations
Vereshchagin, S. V.; Chupina, N. V.; Tutukov, A. V.; Sizova, M. D.; Postnikova, E. S.
Russia
Abstract
The aim of this study is to search for close binary gravitationally bound pairs of open star clusters (CBOCs). We divided the observed pairs of clusters into visual binaries (VBOCs) and close pairs of CBOCs. Close pairs are physically bound clusters; the distances between them do not exceed 7 pc. These include pairs of clusters whose distances and relative velocities allow their members to be gravitationally linked into binary systems. The analysis of modern catalogs of open clusters has allowed us to select potentially physically related pairs. This paper presents a catalog containing more than 400 VBOC and CBOC pairs. Many of these pairs have been identified for the first time. According to our data, the following three CBOCs are the most promising for a more detailed study: (1) NGC 3590, Hogg 12; (2) ASCC 19, UBC 17a; and (3) Gulliver 6, UBC 17b.