The Frequency of Spectroscopic Binaries in NGC 6475
Abstract
This cluster is known to have unusually low projected rotational velocities among its B stars, in contrast to the Pleiades, a cluster of the same age, which has unusually high rotational velocities. In NGC 6475 eight of the nineteen brightest main-sequence stars are found to be short-period spectroscopic binaries; orbital elements are given for these. This frequency is high relative to that for field stars and especially high relative to that for the Pleiades, among whosc B stars no short-period binaries were found. It is concluded that low rotational velocities are probably caused primarily by tidal interactions in binary systems and that open clusters differ significantly in their binary frequencies.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1970
- DOI:
- 10.1086/150369
- Bibcode:
- 1970ApJ...159..919A