Joseph E. Rodriguez, Harvard-Smithsonian Center for Astrophysics
Jason D. Eastman, Harvard-Smithsonian Center for Astrophysics
George Zhou, Harvard-Smithsonian Center for Astrophysics
Samuel N. Quinn, Harvard-Smithsonian Center for Astrophysics
Thomas G. Beatty, The University of Arizona
Kaloyan Penev, The University of Texas at Dallas
Marshall C. Johnson, The Ohio State University
Phillip A. Cargile, Harvard-Smithsonian Center for Astrophysics
David W. Latham, Harvard-Smithsonian Center for Astrophysics
Allyson Bieryla, Harvard-Smithsonian Center for Astrophysics
Karen A. Collins, Harvard-Smithsonian Center for Astrophysics
Courtney D. Dressing, University of California, Berkeley
David R. Ciardi, National Aeronautics and Space Administration
Howard M. Relles, Harvard-Smithsonian Center for Astrophysics
Gabriel Murawski, Gabriel Murawski Private Observatory (SOTES)
Taku Nishiumi, Kyoto Sangyo University
Atsunori Yonehara, Kyoto Sangyo University
Ryo Ishimaru, Chiba Institute of Technology
Fumi Yoshida, Chiba Institute of Technology
Joao Gregorio, Atalaia Group and CROW Observatory
Michael B. Lund, National Aeronautics and Space Administration
Daniel J. Stevens, Pennsylvania State University
Keivan G. Stassun, Vanderbilt University
B. Scott Gaudi, The Ohio State University
Knicole D. Colón, NASA Goddard Space Flight Center
Joshua Pepper, Lehigh University
Norio Narita, National Institutes of Natural Sciences - National Astronomical Observatory of Japan
Supachai Awiphan, National Astronomical Research Institute of Thailand
Pongpichit Chuanraksasat, National Astronomical Research Institute of Thailand
Paul Benni, Acton Sky Portal (Private Observatory)
Roberto Zambelli, Società Astronomica
Lehman H. Garrison, Harvard-Smithsonian Center for Astrophysics
Maurice L. Wilson, Harvard-Smithsonian Center for Astrophysics

Document Type


Publication Date



We present the discovery of KELT-24 b, a massive hot Jupiter orbiting a bright (V = 8.3 mag, K = 7.2 mag) young F-star with a period of 5.6 days. The host star, KELT-24 (HD 93148), has a Teff = 6509-+4950 K, a mass of M* = 1.460-+0.0590.055 Me, a radius of R* = 1.506 ± 0.022 Re, and an age of 0.78-+0.420.61 Gyr. Its planetary companion (KELT-24 b) has a radius of RP = 1.272 ± 0.021 RJ and a mass of MP = 5.18-+0.220.21 MJ, and from Doppler tomographic observations, we find that the planet’s orbit is well-aligned to its host star’s projected spin axis (l = 2.6-+3.65.1). The young age estimated for KELT-24 suggests that it only recently started to evolve from the zero-age main sequence. KELT-24 is the brightest star known to host a transiting giant planet with a period between 5 and 10 days. Although the circularization timescale is much longer than the age of the system, we do not detect a large eccentricity or significant misalignment that is expected from dynamical migration. The brightness of its host star and its moderate surface gravity make KELT-24b an intriguing target for detailed atmospheric characterization through spectroscopic emission measurements since it would bridge the current literature results that have primarily focused on lower mass hot Jupiters and a few brown dwarfs.

Publication Source (Journal or Book title)

Astronomical Journal