The Difference between Metal-poor and Metal-rich Binaries
Abstract
I explored the reason why many authors differed as to whether the field metal-poor stars are deficient in spectroscopic binaries or have the same frequency as metal-rich stars. From published studies of five large samples of binaries, it is obvious that the distribution of orbital periods of metal-poor stars peaks at 875 days while that of metal-rich stars peaks at about 22 days. That means that if one uses high-dispersion spectra, one will find many binaries in both samples but if one uses low-dispersion spectra, one will fail to detect the long-period binaries and will find more binaries among the metal-rich stars. The reason for the difference in period distributions seems to be that most of the metal-poor stars have left the globular clusters quickly (within 10^6 yr), before most of them can form short-period binaries in three-body encounters.
- Publication:
-
The Eighth Pacific Rim Conference on Stellar Astrophysics: A Tribute to Kam-Ching Leung
- Pub Date:
- August 2009
- Bibcode:
- 2009ASPC..404..209A