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Measuring the Recoverability of Close Binaries in Gaia DR2 with the Robo-AO Kepler Survey

Ziegler, Carl and Law, Nicholas M. and Baranec, Christoph and Morton, Tim and Riddle, Reed and De Lee, Nathan and Huber, Daniel and Mahadevan, Suvrath and Pepper, Joshua (2018) Measuring the Recoverability of Close Binaries in Gaia DR2 with the Robo-AO Kepler Survey. Astronomical Journal, 156 (6). Art. No. 259. ISSN 1538-3881.

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We use the Robo-AO survey of Kepler planetary candidate host stars, the largest adaptive optics survey yet performed, to measure the recovery rate of close stellar binaries in Gaia DR2. We find that Gaia recovers binaries down to 1'' at magnitude contrasts as large as six; closer systems are not resolved, regardless of secondary brightness. Gaia DR2 binary detection does not have a strong dependence on the orientation of the stellar pairs. We find 177 nearby stars to Kepler planetary candidate host stars in Gaia DR2 that were not detected in the Robo-AO survey, almost all of which are faint (G > 20); the remainder were largely targets observed by Robo-AO in poor conditions. If the primary star is the host, the impact on the radii estimates of planet candidates in these systems is likely minimal; many of these faint stars, however, could be faint eclipsing binaries that are the source of a false positive planetary transit signal. With Robo-AO and Gaia combined, we find that 18.7 ± 0.7% of Kepler planet candidate hosts have nearby stars within 4''. We also find 36 nearby stars in Gaia DR2 around 35 planetary candidate host stars detected with K2. The nearby star fraction rate for K2 planetary candidates is significantly lower than that for the primary Kepler mission. The binary recovery rate of Gaia will improve initial radius estimates of future Transiting Exoplanet Survey Satellite planet candidates significantly; however, ground-based high-resolution follow-up observations are still needed for precise characterization and confirmation. The sensitivity of Gaia to closely separated binaries is expected to improve in later data releases.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ziegler, Carl0000-0002-0619-7639
Law, Nicholas M.0000-0001-9380-6457
Baranec, Christoph0000-0002-1917-9157
Morton, Tim0000-0002-8537-5711
Riddle, Reed0000-0002-0387-370X
De Lee, Nathan0000-0002-3657-0705
Huber, Daniel0000-0001-8832-4488
Mahadevan, Suvrath0000-0001-9596-7983
Pepper, Joshua0000-0002-3827-8417
Additional Information:© 2018. The American Astronomical Society. Received 2018 June 25; revised 2018 June 29; accepted 2018 July 6; published 2018 November 9. This work uses data from research supported by the NASA Exoplanets Research Program, grant #NNX 15AC91G. C.Z. is supported by a Dunlap Fellowship at the Dunlap Institute for Astronomy & Astrophysics, funded through an endowment established by the Dunlap family and the University of Toronto. C.B. acknowledges support from the Alfred P. Sloan Foundation. T.M is supported by NASA grant #NNX 14AE11G under the Kepler Participating Scientist Program. S.M. acknowledges support from the National Science Foundation award AST-1517592. D.H. acknowledges support by the National Science Foundation (AST-1717000) and the National Aeronautics and Space Administration under grant NNX14AB92G issued through the Kepler Participating Scientist Program. The authors thank the Research Corporation for hosting the 2018 Time Domain Astronomy Scialog, where the idea for this project originated. The Robo-AO team thanks NSF and NOAO for making the Kitt Peak 2.1 m telescope available. Robo-AO KP is a partnership between the California Institute of Technology, the University of Hawaii, the University of North Carolina at Chapel Hill, the Inter-University Centre for Astronomy and Astrophysics (IUCAA) at Pune, India, and the National Central University, Taiwan. The Murty family feels very happy to have added a small value to this important project. Robo-AO KP is also supported by grants from the John Templeton Foundation and the Mt. Cuba Astronomical Foundation. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This work has 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. This work made use of the crossmatch database created by Megan Bedell. We thank the anonymous referee for her or his careful analysis and useful comments on the manuscript. Facilities: PO:1.5m (Robo-AO) - , KPNO:2.1m (Robo-AO) - , Gaia - .
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Dunlap Institute for Astronomy and AstrophysicsUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
John Templeton FoundationUNSPECIFIED
Mt. Cuba Astronomical FoundationUNSPECIFIED
Gaia Multilateral AgreementUNSPECIFIED
Subject Keywords:binaries: close; instrumentation: adaptive optics; methods: data analysis; methods: observational; techniques: high angular resolution
Record Number:CaltechAUTHORS:20181113-112609569
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Official Citation:Carl Ziegler et al 2018 AJ 156 259
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90867
Deposited By: George Porter
Deposited On:14 Nov 2018 00:13
Last Modified:21 Mar 2019 22:02

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