Allyson Bieryla, Harvard-Smithsonian Center for Astrophysics
Karen Collins, University of Louisville
Thomas G. Beatty, Pennsylvania State University
Jason Eastman, Harvard-Smithsonian Center for Astrophysics
Robert J. Siverd, Las Cumbres Observatory Global Telescope Network, Inc
Joshua Pepper, Lehigh University
B. Scott Gaudi, The Ohio State University
Keivan G. Stassun, Vanderbilt University
Caleb Cañas, Harvard-Smithsonian Center for Astrophysics
David W. Latham, Harvard-Smithsonian Center for Astrophysics
Lars A. Buchhave, Harvard-Smithsonian Center for Astrophysics
Roberto Sanchis-Ojeda, University of California, Berkeley
Joshua N. Winn, MIT Kavli Institute for Astrophysics and Space Research
Eric L.N. Jensen, Swarthmore College
John F. Kielkopf, University of Louisville
Kim K. McLeod, Wellesley College
Joao Gregorio, Atalaia Group and CROW Observatory
Knicole D. Colón, Lehigh University
Rachel Street, Las Cumbres Observatory Global Telescope Network, Inc
Rachel Ross, Las Cumbres Observatory Global Telescope Network, Inc
Matthew Penny, The Ohio State University
Samuel N. Mellon, Westminster College, New Wilmington
Thomas E. Oberst, Westminster College, New Wilmington
Benjamin J. Fulton, University Hawaii Institute for Astronomy
Ji Wang, Yale University
Perry Berlind, Harvard-Smithsonian Center for Astrophysics
Michael L. Calkins, Harvard-Smithsonian Center for Astrophysics
Gilbert A. Esquerdo, Harvard-Smithsonian Center for Astrophysics
Darren L. Depoy, Texas A&M University
Andrew Gould, The Ohio State University
Jennifer Marshall, Texas A&M University
Richard Pogge, The Ohio State University
Mark Trueblood, Winer Observatory

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We report the discovery of KELT-7b, a transiting hot Jupiter with a mass of 1.28 ± 0.18MJ, radius of 1.533 0.0470.046RJ, and an orbital period of 2.7347749 ± 0.0000039 days. The bright host star (HD 33643; KELT-7) is an F-star with V = 8.54, Teff= 6789 4950 K, [Fe/H] 0.139 0.081 = -0.075, and log g = 4.149 ± 0.019. It has a mass of 1.535 0.0540.066 Me, a radius of 1.732 0.0450.043 Re, and is the fifth most massive, fifth hottest, and the ninth brightest star known to host a transiting planet. It is also the brightest star around which Kilodegree Extremely Little Telescope (KELT) has discovered a transiting planet. Thus, KELT-7b is an ideal target for detailed characterization given its relatively low surface gravity, high equilibrium temperature, and bright host star. The rapid rotation of the star (73 ± 0.5 km s-1) results in a RossiterMcLaughlin effect with an unusually large amplitude of several hundred m s-1. We find that the orbit normal of the planet is likely to be well-aligned with the stellar spin axis, with a projected spin orbit alignment of = 9.7 ± 5. 2. This is currently the second most rapidly rotating star to have a reflex signal (and thus mass determination) due to a planetary companion measured.

Publication Source (Journal or Book title)

Astronomical Journal