Allyson Bieryla, Karen Collins, Thomas G. Beatty, Jason Eastman, Robert J. Siverd, Joshua Pepper, B. Scott Gaudi, Keivan G. Stassun, Caleb Cañas, David W. Latham, Lars A. Buchhave, Roberto Sanchis-Ojeda, Joshua N. Winn, Eric L.N. Jensen, John F. Kielkopf, Kim K. McLeod, Joao Gregorio, Knicole D. Colón, Rachel Street, Rachel RossMatthew Penny, Samuel N. Mellon, Thomas E. Oberst, Benjamin J. Fulton, Ji Wang, Perry Berlind, Michael L. Calkins, Gilbert A. Esquerdo, Darren L. Depoy, Andrew Gould, Jennifer Marshall, Richard Pogge, Mark Trueblood, Patricia Trueblood

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


We report the discovery of KELT-7b, a transiting hot Jupiter with a mass of 1.28 ± 0.18MJ, radius of 1.533 0.047 0.046RJ, 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 49 50 K, [Fe/H] 0.139 0.081 = -0.075, and log g = 4.149 ± 0.019. It has a mass of 1.535 0.054 0.066 Me, a radius of 1.732 0.045 0.043 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.

Original languageEnglish (US)
Article number12
JournalAstronomical Journal
Issue number1
StatePublished - Jul 1 2015
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • planetary systems
  • stars: individual (KELT)
  • techniques: photometric
  • techniques: spectroscopic


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