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Eclipsing binaries in the open cluster Ruprecht 147. II: EPIC 219568666

Torres, Guillermo and Vanderburg, Andrew and Curtis, Jason L. and Ciardi, David and Kraus, Adam L. and Rizzuto, Aaron C. and Ireland, Michael J. and Lund, Michael B. and Christiansen, Jessie L. and Beichman, Charles A. (2019) Eclipsing binaries in the open cluster Ruprecht 147. II: EPIC 219568666. Astrophysical Journal, 887 (2). Art. No. 109. ISSN 1538-4357. doi:10.3847/1538-4357/ab54c5.

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We report our spectroscopic monitoring of the detached, grazing, and slightly eccentric 12 day double-lined eclipsing binary EPIC 219568666 in the old nearby open cluster Ruprecht 147. This is the second eclipsing system to be analyzed in this cluster, following our earlier study of EPIC 219394517. Our analysis of the radial velocities combined with the light curve from the K2 mission yields absolute masses and radii for EPIC 219568666 of M₁ = 1.121 ± 0.013 M☉ and R₁ = 1.1779 ± 0.0070 R☉ for the F8 primary and M₂ = 0.7334 ± 0.0050 M☉ and R₂ = 0.640 ± 0.017 R☉ for the faint secondary. Comparison with current stellar evolution models calculated for the known metallicity of the cluster points to a primary star that is oversized, as is often seen in active M dwarfs, but this seems rather unlikely for a star of its mass and with a low level of activity. Instead, we suspect a subtle bias in the radius ratio inferred from the photometry, despite our best efforts to avoid it, which may be related to the presence of spots on one or both stars. The radius sum for the binary, which bypasses this possible problem, indicates an age of 2.76 ± 0.61 Gyr, which is in good agreement with a similar estimate from the binary in our earlier study.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Torres, Guillermo0000-0002-5286-0251
Vanderburg, Andrew0000-0001-7246-5438
Curtis, Jason L.0000-0002-2792-134X
Ciardi, David0000-0002-5741-3047
Kraus, Adam L.0000-0001-9811-568X
Rizzuto, Aaron C.0000-0001-9982-1332
Ireland, Michael J.0000-0002-6194-043X
Lund, Michael B.0000-0003-2527-1598
Christiansen, Jessie L.0000-0002-8035-4778
Beichman, Charles A.0000-0002-5627-5471
Additional Information:© 2019 The American Astronomical Society. Received 2019 October 1; revised 2019 November 4; accepted 2019 November 4; published 2019 December 16. The spectroscopic observations of EPIC 219568666 were gathered with the help of P. Berlind, M. Calkins, G. Esquerdo, and D. Latham. J. Mink is thanked for maintaining the CfA echelle database. We are also grateful to J. Irwin for implementing changes in the eb program that facilitated the present analysis, and to the anonymous referee for helpful comments and suggestions. G.T. acknowledges partial support from NASA's Astrophysics Data Analysis Program through grant 80NSSC18K0413, and to the National Science Foundation (NSF) through grant AST-1509375. J.L.C. is supported by the NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1602662, and by NASA under grant NNX16AE64G issued through the K2 Guest Observer Program (GO 7035). This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. The research has made use of the SIMBAD and VizieR databases, operated at the CDS, Strasbourg, France, and of NASA's Astrophysics Data System Abstract Service. The research was made possible through the use of the AAVSO Photometric All-Sky Survey (APASS), funded by the Robert Martin Ayers Sciences Fund. Data products were also used from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by NASA and the NSF. The work has also made use of data from the European Space Agency (ESA) mission Gaia (, processed by the Gaia Data Processing and Analysis Consortium (DPAC, Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. The computational resources used for this research include the Smithsonian Institution's "Hydra" High Performance Cluster.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NSF Astronomy and Astrophysics FellowshipAST-1602662
Robert Martin Ayers Sciences FundUNSPECIFIED
Gaia Multilateral AgreementUNSPECIFIED
Subject Keywords:Eclipsing binary stars; Open star clusters; Stellar evolutionary models; Light curves; Fundamental parameters of stars; Stellar ages
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Eclipsing binary stars (444); Open star clusters (1160); Stellar evolutionary models (2046); Light curves (918); Fundamental parameters of stars (555); Stellar ages (1581)
Record Number:CaltechAUTHORS:20191122-092222597
Persistent URL:
Official Citation:Guillermo Torres et al 2019 ApJ 887 109
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:100011
Deposited By: Tony Diaz
Deposited On:22 Nov 2019 17:55
Last Modified:16 Nov 2021 17:51

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