WIYN Open Cluster Study: Orbital Solutions for Hard Binaries of NGC 6819

Type Conference Paper
Names Katelyn Milliman, R. Mathieu, A. M. Geller, N. M. Gosnell, S. Meibom
Proceedings Title Bulletin of the American Astronomical Society
Conference Name American Astronomical Society, AAS Meeting #219, #153.36
Volume 219
Date January 1, 2012
Short Title WIYN Open Cluster Study
URL http://adsabs.harvard.edu/abs/2012AAS...21915336M
Library Catalog NASA ADS
Abstract As part of the WIYN Open Cluster Study (WOCS) we have underway a comprehensive stellar radial-velocity survey of the intermediate-age (2.5 Gyr) open cluster NGC 6819. Over more than a decade, we have obtained over 12,000 spectra of more than 2000 stars with 11 < V < 16.5. Our sample includes upper main sequence stars, giants, and most potential blue stragglers, as well as some interesting X-ray sources, including a rapidly rotating sub-subgiant. Given the excellent precision (our error is ≈ 0.4 km/sec) of the radial-velocity measurements we are able to confidently separate field stars and cluster members. We have detected over 150 velocity variable stars, for which we have more than 75 completed orbital solutions; 51 of these are cluster members. This large sample will allow definition of the NGC 6819's short-period binary population, including mass segregation, the period-eccentricity distribution, and the frequency of the short-period hard-binaries that drive the cluster evolution. This work was supported by the National Science Foundation through NSF Award AST-0908082.
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