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arXiv · 2003.09732

WIYN Open Cluster Study. LXXVII. Radial-Velocity Measurements and Spectroscopic Binary Orbits in the Open Cluster NGC 7789

Andrew C. Nine·Katelyn E. Milliman·Robert D. Mathieu·Aaron M. Geller·Emily M. Leiner·Imants Platais·Benjamin M. Tofflemire
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Abstract

We introduce the stellar sample of the WIYN Open Cluster Study radial-velocity survey for the rich open cluster NGC 7789 (1.6 Gyr, [Fe/H] = +0.02). This sample lies within an 18$'$ circular radius from the cluster center (10 pc in projection, or about 2 core radii), and includes giants, red-clump stars, blue stragglers, red stragglers, sub-subgiants, and main-sequence stars down to one mag below the turnoff. Our survey began in 2005 and comprises more than 9,000 radial-velocity measurements from the Hydra Multi-Object Spectrograph on the WIYN 3.5m telescope. We identify 564 likely cluster members and present the orbital solutions for 83 cluster binary stars with periods between 1.45$\,$d and 4200$\,$d. From the main-sequence binary solutions we fit a circularization period of 8.22$^{+3.51}_{-1.35}\,$d. We calculate an incompleteness-corrected main-sequence binary frequency of 31% $\pm$ 3% for binaries with periods less than 10$^{4}$ days, similar to other WOCS open clusters of all ages. We detect a blue straggler binary frequency of 31% $\pm$ 15%, consistent with the similarly aged cluster NGC 6819.

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Andrew C. Nine, Katelyn E. Milliman, Robert D. Mathieu, Aaron M. Geller, Emily M. Leiner, Imants Platais, Benjamin M. Tofflemire. 2020-03-21. WIYN Open Cluster Study. LXXVII. Radial-Velocity Measurements and Spectroscopic Binary Orbits in the Open Cluster NGC 7789. https://doi.org/10.3847/1538-3881%2Fabad3b

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