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KELT-23Ab: A Hot Jupiter Transiting a Near-solar Twin Close to the TESS and JWST Continuous Viewing Zones

Johnson, Daniel and Fulton, Benjamin J. and Ciardi, David R. and Lund, Michael B. (2019) KELT-23Ab: A Hot Jupiter Transiting a Near-solar Twin Close to the TESS and JWST Continuous Viewing Zones. Astronomical Journal, 158 (2). Art. No. 78. ISSN 1538-3881. doi:10.3847/1538-3881/ab24c7.

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We announce the discovery of KELT-23Ab, a hot Jupiter transiting the relatively bright (V = 10.3) star BD+66 911 (TYC 4187-996-1), and characterize the system using follow-up photometry and spectroscopy. A global fit to the system yields host-star properties of T_(eff)=5900±49K, M∗=0.945^(+0.060)_(−0.054)M⊙, R∗=0.995±0.015R⊙, L∗=1.082^(+0.051)_(−0.048)L⊙, logg∗=4.418^(+0.026)_(−0.025) (cgs), and [Fe/H]=−0.105±0.077. KELT-23Ab is a hot Jupiter with a mass of MP=0.938^(+0.045)_(−0.042)M_J, radius of R_P=1.322±0.025RJ, and density of ρ_P=0.504^(+0.038)_(−0.035) g cm^(−3). Intense insolation flux from the star has likely caused KELT-23Ab to become inflated. The time of inferior conjunction is T_0=2458149.40776±0.00091 BJD_(TDB) and the orbital period is P=2.255353^(+0.000031)_(−0.00003) days. There is strong evidence that KELT-23A is a member of a long-period binary star system with a less luminous companion, and due to tidal interactions, the planet is likely to spiral into its host within roughly a gigayear. This system has one of the highest positive ecliptic latitudes of all transiting planet hosts known to date, placing it near the Transiting Planet Survey Satellite and James Webb Space Telescope continuous viewing zones. Thus we expect it to be an excellent candidate for long-term monitoring and follow up with these facilities.

Item Type:Article
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URLURL TypeDescription Paper
Johnson, Daniel0000-0001-6311-8629
Fulton, Benjamin J.0000-0003-3504-5316
Ciardi, David R.0000-0002-5741-3047
Lund, Michael B.0000-0003-2527-1598
Additional Information:© 2019 The American Astronomical Society. Received 2019 February 27; revised 2019 May 21; accepted 2019 May 23; published 2019 July 24. This project makes use of data from the KELT survey, including support from The Ohio State University, Vanderbilt University, and Lehigh University, along with the KELT follow-up collaboration. Work performed by J.E.R. was supported by the Harvard Future Faculty Leaders Postdoctoral fellowship. D.J.S. and B.S.G. were partially supported by NSF CAREER Grant AST-1056524. Work by S.V.Jr. is supported by the National Science Foundation Graduate Research Fellowship under grant No. DGE-1343012. Work by G.Z. is provided by NASA through Hubble Fellowship grant HST-HF2-51402.001-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 NAS 5-26555. This paper includes data taken at The McDonald Observatory of The University of Texas at Austin. This work has made use of NASA's Astrophysics Data System, the Extrasolar Planet Encyclopedia, the NASA Exoplanet Archive, the SIMBAD database operated at CDS, Strasbourg, France, and the VizieR catalog access tool, CDS, Strasbourg, France. We make use of Filtergraph, an online data visualization tool developed at Vanderbilt University through the Vanderbilt Initiative in Data-intensive Astrophysics (VIDA). We also used data products from the Widefield Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles; the Jet Propulsion Laboratory/California Institute of Technology, which is funded by the National Aeronautics and Space Administration; 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 the National Aeronautics and Space Administration and the National Science Foundation; and 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. Any opinions, findings, and conclusions or recommendations expressed are those of the authors and do not necessarily reflect the views of the National Science Foundation. This material is based upon work supported by the National Science Foundation under grant No. 1559487. K.P. acknowledges support from NASA grants 80NSSC18K1009 and NNX17AB94G. We thank Alex Jensen for observations that contributed to this work. J.L. acknowledges support from FAPESP (grant 2017/23731-1). We also thank the anonymous referee for valuable comments that improved this manuscript. D.J. acknowledges support from the Carol and Ray Neag Undergraduate Research Fund. Software:numpy (Oliphant 2015), matplotlib (Hunter 2007), scipy, (Jones et al. 2001), astropy, (Price-Whelan et al. 2018).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Ohio State UniversityUNSPECIFIED
Vanderbilt UniversityUNSPECIFIED
Lehigh UniversityUNSPECIFIED
Harvard UniversityUNSPECIFIED
NSF Graduate Research FellowshipDGE-1343012
NASA Hubble FellowshipHST-HF2-51402.001-A
NASANAS 5-26555
Gaia Multilateral AgreementUNSPECIFIED
Fundação de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP)2017/23731-1
Kutztown UniversityUNSPECIFIED
Subject Keywords:methods: observational – planets and satellites: detection – planets and satellites: gaseous planets – techniques: photometric – techniques: radial velocities – techniques: spectroscopic
Issue or Number:2
Record Number:CaltechAUTHORS:20190724-093317753
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Official Citation:Daniel Johns et al 2019 AJ 158 78
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97386
Deposited By: Tony Diaz
Deposited On:24 Jul 2019 18:13
Last Modified:16 Nov 2021 17:31

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