KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating Metal-poor Late-A Primary of a Likely Hierarchical Triple System
Article
Article Title | KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating Metal-poor Late-A Primary of a Likely Hierarchical Triple System |
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ERA Journal ID | 1048 |
Article Category | Article |
Authors | Johnson, Marshall C. (Author), Rodriguez, Joseph E. (Author), Zhou, George (Author), Gonzales, Erica J. (Author), Cargile, Phillip A. (Author), Crepp, Justin R. (Author), Penev, Kaloyan (Author), Stassun, Keivan G. (Author), Gaudi, B. Scott (Author), Colon, Knicole D. (Author), Stevens, Daniel J. (Author), Strassmeier, Klaus G. (Author), Ilyin, Ilya (Author), Collins, Karen A. (Author), Kielkopf, John F. (Author), Oberst, Thomas E. (Author), Maritch, Luke (Author), Reed, Phillip A. (Author), Gregorio, Joao (Author), Bozza, Valerio (Author), Calchi Novati, Sebastiano (Author), D'Ago, Giuseppe (Author), Scarpetta, Gaetano (Author), Zambelli, Roberto (Author), Latham, David W. (Author), Bieryla, Allyson (Author), Cochran, William D. (Author), Endl, Michael (Author), Tayar, Jamie (Author), Serenelli, Aldo (Author), Aguirre, Victor Silva (Author), Clarke, Seth P. (Author), Martinez, Maria (Author), Spencer, Michelle (Author), Trump, Jason (Author), Joner, Michael D. (Author), Bugg, Adam G. (Author), Hintz, Eric G. (Author), Stephens, Denise C. (Author), Arredondo, Anicia (Author), Benzaid, Anissa (Author), Yazdi, Sormeh (Author), McLeod, Kim K. (Author), Jensen, Eric L. N. (Author), Hancock, Daniel A. (Author), Sorber, Rebecca L. (Author), Kasper, David H. (Author), Jang-Condell, Hannah (Author), Beatty, Thomas G. (Author), Carroll, Thorsten (Author), Eastman, Jason (Author), James, David (Author), Kuhn, Rudolf B. (Author), Labadie-Bartz, Jonathan (Author), Lund, Michael B. (Author), Mallonn, Matthias (Author), Pepper, Joshua (Author), Siverd, Robert J. (Author), Yao, Xinyu (Author), Cohen, David H. (Author), Curtis, Ivan A. (Author), DePoy, D. L. (Author), Fulton, Benjamin J. (Author), Penny, Matthew T. (Author), Relles, Howard (Author), Stockdale, Christopher (Author), Tan, Thiam-Guan (Author) and Villanueva, Steven, Jr. (Author) |
Journal Title | The Astronomical Journal |
Journal Citation | 155 (2), pp. 1-20 |
Article Number | 100 |
Number of Pages | 20 |
Year | 2018 |
Publisher | IOP Publishing |
Place of Publication | United States |
ISSN | 0004-6256 |
1538-3881 | |
Digital Object Identifier (DOI) | https://doi.org/10.3847/1538-3881/aaa5af |
Web Address (URL) | https://iopscience.iop.org/article/10.3847/1538-3881/aaa5af |
Abstract | We present the discovery of KELT-21b, a hot Jupiter transiting the V = 10.5 A8V star HD 332124. The planet has an orbital period of P = 3.6127647 ± 0.0000033 days and a radius of 1.586-0.040+0.039 RJ. We set an upper limit on the planetary mass of at confidence. We confirmed the planetary nature of the transiting companion using this mass limit and Doppler tomographic observations to verify that the companion transits HD 332124. These data also demonstrate that the planetary orbit is well-aligned with the stellar spin, with a sky-projected spin-orbit misalignment of λ = -5.6-1.91.7. The star has Teff = 7598-8481 K, Mz.ast; = 1.458-0.028+0.029 M⊙, Rz.ast; = 1.638 ± 0.034 R⊙ and v sin I∗ = 146 km s-1, the highest projected rotation velocity of any star known to host a transiting hot Jupiter. The star also appears to be somewhat metal poor and α-enhanced, with [Fe/H] = -405-0.033+0.032 and [α/Fe] = 0.145 ± 0.053; these abundances are unusual, but not extraordinary, for a young star with thin-disk kinematics like KELT-21. High-resolution imaging observations revealed the presence of a pair of stellar companions to KELT-21, located at a separation of 1.″2 and with a combined contrast of ΔKs = 6.39 ± 0.06 with respect to the primary. Although these companions are most likely physically associated with KELT-21, we cannot confirm this with our current data. If associated, the candidate companions KELT-21 B and C would each have masses of ∼0.12 M⊙, a projected mutual separation of ∼20 au, and a projected separation of ∼500 au from KELT-21. KELT-21b may be one of only a handful of known transiting planets in hierarchical triple stellar systems. |
Keywords | methods: observational; planets and satellites: detection; planets and satellites: gaseous planets; stars: individual (HD 332124); techniques: photometric; techniques: radial velocities; Astrophysics - Earth and Planetary Astrophysics; Astrophysics - Astrophysics of Galaxies |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | File reproduced in accordance with the copyright policy of the publisher/author. |
Institution of Origin | University of Southern Queensland |
Byline Affiliations | Ohio State University, United States |
Center for Astrophysics Harvard and Smithsonian, United States | |
University of California, United States | |
University of Notre Dame, United States | |
University of Texas at Dallas, United States | |
Vanderbilt University, United States | |
NASA Goddard Space Flight Center, United States | |
Leibniz Institute for Astrophysics, Germany | |
School of Mathematics, Physics and Computing | |
Westminster College, United States | |
Kutztown University, United States | |
Atalaia Group and CROW Observatory, Portugal | |
University of Salerno, Italy | |
National Institute for Astrophysics, Italy | |
Lunae Astronomical Society, Italy | |
University of Texas at Austin, United States | |
Ohio University, United States | |
University of Barcelona, Spain | |
Aarhus University, Denmark | |
Brigham Young University, United States | |
Wellesley College, United States | |
Swarthmore College, United States | |
Aarhus University, Denmark | |
Pennsylvania State University, United States | |
South African Astronomical Observatory, South Africa | |
Lehigh University, United States | |
Las Cumbres Observatory, United States | |
Ivan Curtis Private Observatory, Australia | |
Texas A&M University, United States | |
California Institute of Technology (Caltech), United States | |
Hazelwood Observatory, Australia | |
Perth Exoplanet Survey Telescope Observatory, Australia |
https://research.usq.edu.au/item/q6x45/kelt-21b-a-hot-jupiter-transiting-the-rapidly-rotating-metal-poor-late-a-primary-of-a-likely-hierarchical-triple-system
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