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EPIC 201702477b: A Transiting Brown Dwarf from K2 in a 41 day Orbit

Bayliss, D. and Mawet, D. and Fulton, B. and Ngo, H. and Petigura, E. and Fulton, B. (2017) EPIC 201702477b: A Transiting Brown Dwarf from K2 in a 41 day Orbit. Astronomical Journal, 153 (1). Art. No. 15. ISSN 0004-6256. doi:10.3847/1538-3881/153/1/15.

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We report the discovery of EPIC 201702477b, a transiting brown dwarf in a long period (40.73691 ± 0.00037 day) and eccentric (e = 0.2281 ± 0.0026) orbit. This system was initially reported as a planetary candidate based on two transit events seen in K2 Campaign 1 photometry and later validated as an exoplanet candidate. We confirm the transit and refine the ephemeris with two subsequent ground-based detections of the transit using the Las Cumbres Observatory Global Telescope 1 m telescope network. We rule out any transit timing variations above the level of ~30 s. Using high precision radial velocity measurements from HARPS and SOPHIE we identify the transiting companion as a brown dwarf with a mass, radius, and bulk density of 66.9 ± 1.7 M_J, 0.757 ± 0.065 R_J, and 191 ± 51 g cm^(−3) respectively. EPIC 201702477b is the smallest radius brown dwarf yet discovered, with a mass just below the H-burning limit. It has the highest density of any planet, substellar mass object, or main-sequence star discovered so far. We find evidence in the set of known transiting brown dwarfs for two populations of objects—high mass brown dwarfs and low mass brown dwarfs. The higher-mass population have radii in very close agreement to theoretical models, and show a lower-mass limit around 60 M_J. This may be the signature of mass-dependent ejection of systems during the formation process.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Bayliss, D.0000-0001-6023-1335
Mawet, D.0000-0002-8895-4735
Fulton, B.0000-0003-3504-5316
Ngo, H.0000-0001-5172-4859
Petigura, E.0000-0003-0967-2893
Fulton, B.0000-0003-3504-5316
Alternate Title:EPIC201702477b: A Long Period Transiting Brown Dwarf from K2
Additional Information:© 2016 The American Astronomical Society. Received 2016 June 3; revised 2016 September 29; accepted 2016 October 14; published 2016 December 20. This work has been carried out within the framework of the National Centre for Competence in Research "PlanetS" supported by the Swiss National Science Foundation (SNSF). This paper includes data collected by the K2 mission. Funding for the K2 mission is provided by the NASA Science Mission directorate. This paper makes use of data and services from NASA Exoplanet Archive (Akeson et al. 2013), which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. We are grateful to our colleagues who have performed some of the observations presented here with the HARPS spectrograph: F. Motalebi, A. Wyttenbach, and B. Lavie. The Porto group acknowledges the support from the Fundação para a Ciência e Tecnologia, FCT (Portugal) in the form of the grants, projects, and contracts UID/FIS/04434/2013 (POCI-01-0145-FEDER-007672), PTDC/FIS-AST/1526/2014 (POCI-01-0145-FEDER-016886), IF/00169/2012, IF/00028/2014, IF/01312/2014 and POPH/FSE (EC) by FEDER funding through the Programa Operacional de Factores de Competitividade—COMPETE. Partly based on observations made at Observatoire de Haute Provence (CNRS), France and with ESO Telescopes at the La Silla Paranal Observatory under programme ID 096.C-0657. Some of the 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. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. A.S. is supported by the European Union under a Marie Curie Intra-European Fellowship for Career Development with reference FP7-PEOPLE-2013-IEF, number 627202. J.L.-B. acknowledges financial support from the Marie Curie Actions of the European Commission (FP7-COFUND) and the Spanish grant AYA2012-38897-C02-01. J.M.A. acknowledges funding from the European Research Council under the ERC Grant Agreement n. 337591-ExTrA. D.J.A. and D.P. acknowledge funding from the European Union Seventh Framework programme (FP7/2007-2013) under grant agreement No. 313014 (ETAEARTH). O.D. acknowledges support by CNES through contract 567133. S.C.C.B. acknowledges support by the Fundação para a Ciência e Tecnologia, (FCT) through the Investigador FCT Contract No. IF/01312/2014 and the grant reference PTDC/FIS- AST/1526/2014. K.H. and A.C.C. acknowledge support from UK Science and Technology Facilities Council (STFC) grant ST/M001296/1. D. Dragomir acknowledges support provided by NASA through Hubble Fellowship grant HST-HF2-51372.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. D.J.A.B. acknowledges support from the UKSA and the University of Warwick. B.J.F. notes that this material is based upon work supported by the National Science Foundation Graduate Research Fellowship under grant No. 2014184874. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the authors(s) and do not necessarily reflect the views of the National Science Foundation. W.D.C. acknowledges support from NASA Grants NNX15AV58G and NNX16AE70G. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469. This work was performed in part under contract with the Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. Facilities: CAO:2.2m (AstraLux) - , ESO:3.6m (HARPS) - , K2 - , Keck:II (NIRC2) - , Keck:I (HIRES) - , LCOGT - , OHP:1.93m (SOPHIE) - , ANU:2.3m (WiFeS).
Group:Astronomy Department
Funding AgencyGrant Number
Swiss National Science Foundation (SNSF)UNSPECIFIED
Fundação para a Ciência e a Tecnologia (FCT)UID/FIS/04434/2013
Fundação para a Ciência e a Tecnologia (FCT)POCI-01-0145-FEDER-007672
Fundação para a Ciência e a Tecnologia (FCT)PTDC/FIS-AST/1526/2014
Fundação para a Ciência e a Tecnologia (FCT)POCI-01-0145-FEDER-016886
Fundação para a Ciência e a Tecnologia (FCT)IF/00169/2012
Fundação para a Ciência e a Tecnologia (FCT)IF/00028/2014
Fundação para a Ciência e a Tecnologia (FCT)IF/01312/2014
Fonds Européen de Développement Économique et Régional (FEDER)UNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Marie Curie Fellowship627202
Ministerio de Economía y Competitividad (MINECO)AYA2012-38897-C02-01
European Research Council (ERC)337591-ExTrA
European Research Council (ERC)313014
Centre National d'Études Spatiales (CNES)567133
Science and Technology Facilities Council (STFC)ST/M001296/1
NASA Hubble FellowshipHST-HF2-51372.001-A
United Kingdom Space Agency (UKSA)UNSPECIFIED
University of WarwickUNSPECIFIED
NSF Graduate Research Fellowship2014184874
NSF Graduate Research FellowshipDGE-1144469
Subject Keywords:planetary systems – techniques: photometric – techniques: spectroscopic
Issue or Number:1
Record Number:CaltechAUTHORS:20160708-072044484
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Official Citation:EPIC201702477b: A Long Period Transiting Brown Dwarf from K2
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:68902
Deposited By: Ruth Sustaita
Deposited On:09 Jul 2016 04:43
Last Modified:11 Nov 2021 04:06

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