A giant planet undergoing extreme-ultraviolet irradiation by its hot massive-star host
Article
Article Title | A giant planet undergoing extreme-ultraviolet irradiation by its hot massive-star host |
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ERA Journal ID | 17479 |
Article Category | Article |
Authors | Gaudi, B. Scott (Author), Stassun, Keivan G. (Author), Collins, Karen A. (Author), Beatty, Thomas G. (Author), Zhou, George (Author), Latham, David W. (Author), Bieryla, Allyson (Author), Eastman, Jason D. (Author), Siverd, Robert J. (Author), Crepp, Justin R. (Author), Gonzales, Erica J. (Author), Stevens, Daniel J. (Author), Buchhave, Lars A. (Author), Pepper, Joshua (Author), Johnson, Marshall C. (Author), Colon, Knicole D. (Author), Jensen, Eric L. N. (Author), Rodriguez, Joseph E. (Author), Bozza, Valerio (Author), Calchi Novati, Sebastiano (Author), D'Ago, Giuseppe (Author), Dumont, Mary T. (Author), Ellis, Tyler (Author), Gaillard, Clement (Author), Jang-Condell, Hannah (Author), Kasper, David H. (Author), Fukui, Akihiko (Author), Gregorio, Joao (Author), Ito, Ayaka (Author), Kielkopf, John F. (Author), Manner, Mark (Author), Matt, Kyle (Author), Narita, Norio (Author), Oberst, Thomas E. (Author), Reed, Phillip A. (Author), Scarpetta, Gaetano (Author), Stephens, Denice C. (Author), Yeigh, Rex R. (Author), Zambelli, Roberto (Author), Fulton, B. J. (Author), Howard, Andrew W. (Author), James, David J. (Author), Penny, Matthew (Author), Bayliss, Daniel (Author), Curtis, Ivan A. (Author), DePoy, D. L. (Author), Esquerdo, Gilbert A. (Author), Gould, Andrew (Author), Joner, Michael D. (Author), Kuhn, Rudolf B. (Author), Labadie-Bartz, Jonathan (Author), Lund, Michael B. (Author), Marshall, Jennifer L. (Author), McLeod, Kim K. (Author), Pogge, Richard W. (Author), Relles, Howard (Author), Stockdale, Christopher (Author), Tan, T. G. (Author), Trueblood, Mark (Author) and Trueblood, Patricia (Author) |
Journal Title | Nature |
Journal Citation | 546 (7659) |
Number of Pages | 14 |
Year | 2017 |
Publisher | Nature Publishing Group |
Place of Publication | United Kingdom |
ISSN | 0028-0836 |
0090-0028 | |
0300-8746 | |
1476-4687 | |
Digital Object Identifier (DOI) | https://doi.org/10.1038/nature22392 |
Web Address (URL) | https://www.nature.com/articles/nature22392 |
Abstract | The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extrasolar planets now known, only six have been found that transit hot, A-type stars (with temperatures of 7,300-10,000 kelvin), and no planets are known to transit the even hotter B-type stars. For example, WASP-33 is an A-type star with a temperature of about 7,430 kelvin, which hosts the hottest known transiting planet, WASP-33b (ref. 1); the planet is itself as hot as a red dwarf star of type M (ref. 2). WASP-33b displays a large heat differential between its dayside and nightside, and is highly inflated-traits that have been linked to high insolation. However, even at the temperature of its dayside, its atmosphere probably resembles the molecule-dominated atmospheres of other planets and, given the level of ultraviolet irradiation it experiences, its atmosphere is unlikely to be substantially ablated over the lifetime of its star. Here we report observations of the bright star HD 195689 (also known as KELT-9), which reveal a close-in (orbital period of about 1.48 days) transiting giant planet, KELT-9b. At approximately 10,170 kelvin, the host star is at the dividing line between stars of type A and B, and we measure the dayside temperature of KELT-9b to be about 4,600 kelvin. This is as hot as stars of stellar type K4 (ref. 5). The molecules in K stars are entirely dissociated, and so the primary sources of opacity in the dayside atmosphere of KELT-9b are probably atomic metals. Furthermore, KELT-9b receives 700 times more extreme-ultraviolet radiation (that is, with wavelengths shorter than 91.2 nanometres) than WASP-33b, leading to a predicted range of mass-loss rates that could leave the planet largely stripped of its envelope during the main-sequence lifetime of the host star. |
Keywords | ablation; high temperature; insolation; molecular analysis; planetary atmosphere; ultraviolet radiation; Astrophysics - Earth and Planetary Astrophysics |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Institution of Origin | University of Southern Queensland |
Byline Affiliations | Ohio State University, United States |
Vanderbilt University, United States | |
Pennsylvania State University, United States | |
Center for Astrophysics Harvard and Smithsonian, United States | |
Harvard-Smithsonian Centre for Astrophysics, United States | |
Las Cumbres Observatory, United States | |
University of Notre Dame, United States | |
University of Copenhagen, Denmark | |
Lehigh University, United States | |
NASA Ames Research Center, United States | |
Swarthmore College, United States | |
University of Salerno, Italy | |
International Institute for Advanced Scientific Studies, Italy | |
Brigham Young University, United States | |
University of Wyoming, United States | |
National Astronomical Observatory of Japan, Japan | |
Atalaia Group and CROW Observatory, Portugal | |
School of Mathematics, Physics and Computing | |
Spot Observatory, United States | |
Westminster College, United States | |
Kutztown University, United States | |
Lunae Astronomical Society, Italy | |
University of Hawaii, United States | |
University of Washington, United States | |
University of Geneva, Switzerland | |
Ivan Curtis Private Observatory, Australia | |
Texas A&M University, United States | |
South African Astronomical Observatory, South Africa | |
Wellesley College, United States | |
Hazelwood Observatory, Australia | |
Perth Exoplanet Survey Telescope Observatory, Australia | |
Winer Observatory, United States |
https://research.usq.edu.au/item/q6x3w/a-giant-planet-undergoing-extreme-ultraviolet-irradiation-by-its-hot-massive-star-host
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