Two transiting low density sub-Saturns from K2
Article
Article Title | Two transiting low density sub-Saturns from K2 |
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ERA Journal ID | 1057 |
Article Category | Article |
Authors | Petigura, Erik A. (Author), Howard, Andrew W. (Author), Lopez, Eric D. (Author), Deck, Katherine M. (Author), Fulton, Benjamin J. (Author), Crossfield, Ian J. M. (Author), Ciardi, David R. (Author), Chiang, Eugene (Author), Lee, Eve J. (Author), Isaacson, Howard (Author), Beichman, Charles A. (Author), Hansen, Brad M. S. (Author), Schlieder, Joshua E. (Author) and Sinukoff, Evan (Author) |
Journal Title | The Astrophysical Journal: an international review of astronomy and astronomical physics |
Journal Citation | 818 (1), pp. 36-46 |
Article Number | 36 |
Number of Pages | 11 |
Year | 2016 |
Publisher | IOP Publishing |
Place of Publication | United States |
ISSN | 0004-637X |
1538-4357 | |
Digital Object Identifier (DOI) | https://doi.org/10.3847/0004-637X/818/1/36 |
Web Address (URL) | http://iopscience.iop.org/article/10.3847/0004-637X/818/1/36/ |
Abstract | We report the discovery and confirmation of K2-24 b and c, two sub-Saturn planets orbiting a bright (V = 11.3), metal-rich ([Fe/H] = 0.42 ± 0.04 dex) G3 dwarf in the K2 Campaign 2 field. The planets are 5.68 ± 0.56 R⊕ and 7.82 ± 0.72 R⊕ and have orbital periods of 20.8851 ± 0.0003 days and 42.3633 ± 0.0006 days, near the 2:1 mean-motion resonance. We obtained 32 radial velocities with Keck/HIRES and detected the reflex motion due to K2-24 b and c. These planets have masses of 21.0 ± 5.4 M⊕ and 27.0 ± 6.9 M⊕, respectively. With low densities of 0.63 ± 0.25 g cm-3 and 0.31 ± 0.12 g cm-3, respectively, the planets require thick envelopes of H/He to explain their large sizes and low masses. Interior structure models predict that the planets have fairly massive cores of 17.6 ± 4.3 M⊕ and 16.1, ± 4.2 M⊕, respectively. They may have formed exterior to their present locations, accreted their H/He envelopes at large orbital distances, and migrated in as a resonant pair. The proximity to resonance, large transit depths, and host star brightness offers rich opportunities for TTV follow-up. Finally, the low surface gravities of the K2-24 planets make them favorable targets for transmission spectroscopy by Hubble Space Telescope, Spitzer, and James Webb Space Telescope. |
Keywords | planets and satellites; stars; EPIC-203771098; photometric; spectroscopic |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | For access to this article, please click on the URL link provided. |
Byline Affiliations | California Institute of Technology (Caltech), United States |
University of Hawaii, United States | |
University of Edinburgh, United Kingdom | |
University of Arizona, United States | |
National Aeronautics and Space Administration (NASA), United States | |
University of California, United States | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q4350/two-transiting-low-density-sub-saturns-from-k2
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