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Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System

Schwamb, Megan E. and Howard, Andrew W. and Crepp, Justin R. (2013) Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System. Astrophysical Journal, 768 (2). Art. No. 127. ISSN 0004-637X.

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We report the discovery and confirmation of a transiting circumbinary planet (PH1b) around KIC 4862625, an eclipsing binary in the Kepler field. The planet was discovered by volunteers searching the first six Quarters of publicly available Kepler data as part of the Planet Hunters citizen science project. Transits of the planet across the larger and brighter of the eclipsing stars are detectable by visual inspection every ~137 days, with seven transits identified in Quarters 1-11. The physical and orbital parameters of both the host stars and planet were obtained via a photometric-dynamical model, simultaneously fitting both the measured radial velocities and the Kepler light curve of KIC 4862625. The 6.18 ± 0.17 R_⊕ planet orbits outside the 20 day orbit of an eclipsing binary consisting of an F dwarf (1.734 ± 0.044 R_☉, 1.528 ± 0.087 M_☉) and M dwarf (0.378 ± 0.023 R_☉, 0.408 ± 0.024 M_☉). For the planet, we find an upper mass limit of 169 M_⊕ (0.531 Jupiter masses) at the 99.7% confidence level. With a radius and mass less than that of Jupiter, PH1b is well within the planetary regime. Outside the planet's orbit, at ~1000 AU, a previously unknown visual binary has been identified that is likely bound to the planetary system, making this the first known case of a quadruple star system with a transiting planet.

Item Type:Article
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Howard, Andrew W.0000-0001-8638-0320
Crepp, Justin R.0000-0003-0800-0593
Additional Information:© 2013 American Astronomical Society. Received 2012 October 14; accepted 2013 March 22; published 2013 April 23. M.E.S. is supported by a National Science Foundation (NSF) Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1003258 and in part by an American Philosophical Society Franklin Grant. J.A.O. and W.F.W. acknowledge support from the Kepler Participating Scientist Program via NASA grant NNX12AD23G and the NSF via grant AST-1109928. J.A.C. acknowledges NASA support through Hubble Fellowship grants, awarded by STScI, operated by AURA. D.A.F. acknowledges funding support from Yale University and support from the NASA Supplemental Outreach Award, 10-OUTRCH.210-0001. G.T. also acknowledges support from NSF through grant AST-1007992. C.J.L. acknowledges support from The Leverhulme Trust. K.S. acknowledges support from a NASA Einstein Postdoctoral Fellowship grant number PF9-00069, issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8-03060. The Planet Hunters “Talk” discussion tool used was developed at the Adler Planetarium with support from the NSF CDI grant: DRL-0941610. The data presented herein were partly 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. We thank the observers from the California Planet Survey collaboration for their efforts. We thank Mike Brown and Emily Schaller for their assistance in obtaining NGS AO observations. We thank Tom Barclay, Gibor Basri, Luke Dones, Hans Kjeldsen, Hal Levison, and Andrej Prŝa for useful discussions. This paper includes data collected by the Kepler spacecraft, and we gratefully acknowledge the entire Kepler mission team’s efforts in obtaining and providing the light curves used in this analysis. Funding for the Kepler mission is provided by the NASA Science Mission directorate. The publicly released Kepler light curves were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX09AF08G and by other grants and contracts. Facilities: Kepler, Keck:I, Keck:II, SARA
Funding AgencyGrant Number
NSF Astronomy and Astrophysics FellowshipAST-1003258
American Philosophical SocietyUNSPECIFIED
Yale UniversityUNSPECIFIED
Leverhulme TrustUNSPECIFIED
NASA Einstein FellowshipPF9-00069
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:binaries: eclipsing; planets and satellites: detection; planets and satellites: general; stars: individual (KIC 4862625)
Issue or Number:2
Record Number:CaltechAUTHORS:20130604-152402770
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Official Citation:Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System Megan E. Schwamb, Jerome A. Orosz, Joshua A. Carter, William F. Welsh, Debra A. Fischer, Guillermo Torres, Andrew W. Howard, Justin R. Crepp, William C. Keel, Chris J. Lintott, Nathan A. Kaib, Dirk Terrell, Robert Gagliano, Kian J. Jek, Michael Parrish, Arfon M. Smith, Stuart Lynn, Robert J. Simpson, Matthew J. Giguere, and Kevin Schawinski doi:10.1088/0004-637X/768/2/127
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:38792
Deposited By: Ruth Sustaita
Deposited On:04 Jun 2013 22:46
Last Modified:03 Oct 2019 05:00

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