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A Jovian planet in an eccentric 11.5 day orbit around HD 1397 discovered by TESS

Nielsen, L. D. and Ciardi, D. and Beichman, C. (2019) A Jovian planet in an eccentric 11.5 day orbit around HD 1397 discovered by TESS. Astronomy and Astrophysics, 623 . Art. No. A100. ISSN 0004-6361. doi:10.1051/0004-6361/201834577.

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The Transiting Exoplanet Survey Satellite TESS has begun a new age of exoplanet discoveries around bright host stars. We present the discovery of HD 1397b (TOI-120.01), a giant planet in an 11.54-day eccentric orbit around a bright (V = 7.9) G-type subgiant. We estimate both host star and planetary parameters consistently using EXOFASTv2based on TESS time-series photometry of transits and radial velocity measurements with CORALIE and MINERVA-Australis. We also present high angular resolution imaging with NaCo to rule out any nearby eclipsing binaries. We find that HD 1397b is a Jovian planet, with a mass of 0.415 ± 0.020 MJ and a radius of 1.026 ± 0.026 R_J. Characterising giant planets in short-period eccentric orbits, such as HD 1397b, is important for understanding and testing theories for the formation and migration of giant planets as well as planet-star interactions.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Nielsen, L. D.0000-0002-5254-2499
Ciardi, D.0000-0002-5741-3047
Beichman, C.0000-0002-5627-5471
Additional Information:© 2019 ESO. Article published by EDP Sciences. Received 5 November 2018; Accepted 18 February 2019; Published online; 08 March 2019. We thank the Swiss National Science Foundation (SNSF) and the Geneva University for their continuous support to our planet search programs. This work has been in particular carried out in the frame of the National Centre for Competencein Research “PlanetS” supported by the Swiss National Science Foundation (SNSF). This publication makes use of The Data & Analysis Center for Exoplanets (DACE), which is a facility based at the University of Geneva (CH) dedicated to extrasolar planets data visualisation, exchange and analysis. DACE is a platform of the Swiss National Centre of Competence in Research (NCCR) PlanetS, federating the Swiss expertise in Exoplanet research. The DACE platform is available at We acknowledge the use of TESS Alert data, which is currently in a beta test phase, from the TESS Science Office and at the TESS Science Processing Operations Center. Funding for the TESS mission is provided by NASA’s Science Mission directorate. 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 study was in part based on observations collected at the European Southern Observatory under ESO programme 0102.C-0503(A). MINERVA-Australis is supported by Australian Research Council LIEF Grant LE160100001, Discovery Grant DP180100972, Mount Cuba Astronomical Foundation, and institutional partners University of Southern Queensland, MIT, Nanjing University, George Mason University, University of Louisville, University of California Riverside, University of Florida, and University of Texas at Austin.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Swiss National Science Foundation (SNSF)UNSPECIFIED
Geneva UniversityUNSPECIFIED
Gaia Multilateral AgreementUNSPECIFIED
Australian Research CouncilLE16010000
Australian Research CouncilDP180100972
Mt. Cuba Astronomical FoundationUNSPECIFIED
University of Southern QueenslandUNSPECIFIED
Massachusetts Institute of Technology (MIT)UNSPECIFIED
Nanjing UniversityUNSPECIFIED
George Mason UniversityUNSPECIFIED
University of LouisvilleUNSPECIFIED
University of California, RiversideUNSPECIFIED
University of FloridaUNSPECIFIED
University of Texas at AustinUNSPECIFIED
Subject Keywords:planets and satellites: detection – planets and satellites: individual: HD1397b – planets and satellites: individual: TOI-120 – planets and satellites: individual: 394137592
Record Number:CaltechAUTHORS:20190322-093554344
Persistent URL:
Official Citation:A Jovian planet in an eccentric 11.5 day orbit around HD 1397 discovered by TESS. L. D. Nielsen, F. Bouchy, O. Turner, H. Giles, A. Suárez Mascareño, C. Lovis, M. Marmier, F. Pepe, D. Ségransan, S. Udry, J. F. Otegi, G. Ottoni, M. Stalport, G. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins, S. R. Kane, R. A. Wittenmyer, B. Bowler, I. Crossfield, J. Horner, J. Kielkopf, T. Morton, P. Plavchan, C. G. Tinney, Hui Zhang, D. J. Wright, M. W. Mengel, J. T. Clark, J. Okumura, B. Addison, D. A. Caldwell, S. M. Cartwright, K. A. Collins, J. Francis, N. Guerrero, C. X. Huang, E. C. Matthews, J. Pepper, M. Rose, J. Villaseñor, B. Wohler, K. Stassun, S. Howell, D. Ciardi, E. Gonzales, R. Matson, C. Beichman and J. Schlieder A&A, 623 (2019) A100. DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:94043
Deposited By: Tony Diaz
Deposited On:22 Mar 2019 18:07
Last Modified:16 Nov 2021 17:02

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