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WASP-12b and HAT-P-8b are Members of Triple Star Systems

Bechter, Eric B. and Crepp, Justin R. and Ngo, Henry and Knutson, Heather A. and Batygin, Konstantin and Hinkley, Sasha and Muirhead, Philip S. and Johnson, John Asher and Howard, Andrew W. (2014) WASP-12b and HAT-P-8b are Members of Triple Star Systems. Astrophysical Journal, 788 (1). Art. No. 2. ISSN 0004-637X.

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We present high spatial resolution images that demonstrate that WASP-12b and HAT-P-8b orbit the primary stars of hierarchical triple star systems. In each case, two distant companions with colors and brightnesses consistent with M dwarfs co-orbit the hot Jupiter planet host as well as one another. Our adaptive optics images spatially resolve the secondary around WASP-12, previously identified by Bergfors et al. and Crossfield et al. into two distinct sources separated by 84.3 ± 0.6 mas (21 ± 3 AU). We find that the secondary to HAT-P-8, also identified by Bergfors et al., is in fact composed of two stars separated by 65.3 ± 0.5 mas (15 ± 1 AU). Our follow-up observations demonstrate physical association through common proper motion. HAT-P-8 C has a particularly low mass, which we estimate to be 0.18 ± 0.02 M☉ using photometry. Due to their hierarchy, WASP-12 BC and HAT-P-8 BC will enable the first dynamical mass determination for hot Jupiter stellar companions. These previously well studied planet hosts now represent higher-order multi-star systems with potentially complex dynamics, underscoring the importance of diffraction-limited imaging and providing additional context for understanding the migrant population of transiting hot Jupiters.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper DOIArticle
Crepp, Justin R.0000-0003-0800-0593
Ngo, Henry0000-0001-5172-4859
Knutson, Heather A.0000-0002-0822-3095
Batygin, Konstantin0000-0002-7094-7908
Hinkley, Sasha0000-0001-8074-2562
Muirhead, Philip S.0000-0002-0638-8822
Johnson, John Asher0000-0001-9808-7172
Howard, Andrew W.0000-0001-8638-0320
Additional Information:© 2014 The American Astronomical Society. Received 2013 July 25; accepted 2014 April 17; published 2014 May 16. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France. Data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. J.A.J. is supported by generous grants from the David and Lucile Packard Foundation and the Alfred P. Sloan Foundation. B. T. M. is supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE1144469.
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
David and Lucile Packard FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
NSF Graduate Research FellowshipDGE1144469
Subject Keywords:astrometry; stars: individual (WASP-12, HAT-P-8); techniques: high angular resolution; techniques: photometric
Issue or Number:1
Record Number:CaltechAUTHORS:20140708-104037828
Persistent URL:
Official Citation:WASP-12b and HAT-P-8b are Members of Triple Star Systems Eric B. Bechter et al. 2014 ApJ 788 2
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:47074
Deposited By: Tony Diaz
Deposited On:08 Jul 2014 18:15
Last Modified:09 Mar 2020 13:18

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