Investigating the Evolutionary Role and Structure of Binaries in Milky Way Globular Clusters through Correlational Studies of Binary Fraction
Abstract
Poor detection techniques such as radial velocity surveys have limited our understanding of binaries in globular clusters. Theory regarding these systems has instead relied on N-body and Monte Carlo simulations, which depict their significant potential role on a cluster's stellar interactions, core collapse, stellar evaporation, and internal energy. Using observational data recently gathered through the reliable CMD detection method, our project searched for correlations between cluster properties specifically involved in binary simulations and the detected binary fraction. Both monovariate and multivariate approaches enabled us to compare the resulting relationships with those outlined under current models. Our analysis of concentration, core radius, and the central brightness profile provides strong empirical support that binaries delay the onset of core collapse. Furthermore, study of mass function slope and metallicity suggests that existing binaries accelerate stellar evaporation and are not primordial in nature. However, the high binary fraction found in clusters with low velocity dispersion and high absolute magnitudes contradicts theoretical expectations, and raises the possibility that a larger portion of these systems may be soft, rather than hard, binaries. Because modeling of globular clusters relies heavily on the assumption cluster binaries are primarily hard, further data detailing the structure of binary systems is needed to validate our theory and better our understanding of cluster evolution.
- Publication:
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American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22344242R