Water Vapor and Clouds on the Habitable-zone Sub-Neptune Exoplanet K2-18b
Results from the Kepler mission indicate that the occurrence rate of small planets (<3 R ⊕) in the habitable zone of nearby low-mass stars may be as high as 80%. Despite this abundance, probing the conditions and atmospheric properties on any habitable-zone planet is extremely difficult and has r...
| Main Authors: | , , , , , , , , , , , , , , , |
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| 格式: | 文件 |
| 语言: | English |
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American Astronomical Society
2020
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| 在线阅读: | https://hdl.handle.net/1721.1/128227 |
| _version_ | 1826214727369359360 |
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| author | Benneke, Björn Wong, Ian Piaulet, Caroline Knutson, Heather A Lothringer, Joshua Morley, Caroline V Gao, Peter Greene, Thomas P Dressing, Courtney Dragomir, Diana Howard, Andrew W McCullough, Peter R Kempton, Eliza M-R Fortney, Jonathan J Fraine, Jonathan Crossfield, Ian Jm |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Benneke, Björn Wong, Ian Piaulet, Caroline Knutson, Heather A Lothringer, Joshua Morley, Caroline V Gao, Peter Greene, Thomas P Dressing, Courtney Dragomir, Diana Howard, Andrew W McCullough, Peter R Kempton, Eliza M-R Fortney, Jonathan J Fraine, Jonathan Crossfield, Ian Jm |
| author_sort | Benneke, Björn |
| collection | MIT |
| description | Results from the Kepler mission indicate that the occurrence rate of small planets (<3 R ⊕) in the habitable zone of nearby low-mass stars may be as high as 80%. Despite this abundance, probing the conditions and atmospheric properties on any habitable-zone planet is extremely difficult and has remained elusive to date. Here, we report the detection of water vapor and the likely presence of liquid and icy water clouds in the atmosphere of the 2.6 R ⊕ habitable-zone planet K2-18b. The simultaneous detection of water vapor and clouds in the mid-atmosphere of K2-18b is particularly intriguing because K2-18b receives virtually the same amount of total insolation from its host star (1368+114-107 W m-2) as the Earth receives from the Sun (1361 W m-2), resulting in the right conditions for water vapor to condense and explain the detected clouds. In this study we observed nine transits of K2-18b using Hubble Space Telescope/WFC3 in order to achieve the necessary sensitivity to detect the water vapor, and we supplement this data set with Spitzer and K2 observations to obtain a broader wavelength coverage. While the thick hydrogen-dominated envelope we detect on K2-18b means that the planet is not a true Earth analog, our observations demonstrate that low-mass habitable-zone planets with the right conditions for liquid water are accessible with state-of-the-art telescopes. |
| first_indexed | 2024-09-23T16:10:12Z |
| format | Article |
| id | mit-1721.1/128227 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T16:10:12Z |
| publishDate | 2020 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/1282272024-05-15T05:54:32Z Water Vapor and Clouds on the Habitable-zone Sub-Neptune Exoplanet K2-18b Benneke, Björn Wong, Ian Piaulet, Caroline Knutson, Heather A Lothringer, Joshua Morley, Caroline V Gao, Peter Greene, Thomas P Dressing, Courtney Dragomir, Diana Howard, Andrew W McCullough, Peter R Kempton, Eliza M-R Fortney, Jonathan J Fraine, Jonathan Crossfield, Ian Jm Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Results from the Kepler mission indicate that the occurrence rate of small planets (<3 R ⊕) in the habitable zone of nearby low-mass stars may be as high as 80%. Despite this abundance, probing the conditions and atmospheric properties on any habitable-zone planet is extremely difficult and has remained elusive to date. Here, we report the detection of water vapor and the likely presence of liquid and icy water clouds in the atmosphere of the 2.6 R ⊕ habitable-zone planet K2-18b. The simultaneous detection of water vapor and clouds in the mid-atmosphere of K2-18b is particularly intriguing because K2-18b receives virtually the same amount of total insolation from its host star (1368+114-107 W m-2) as the Earth receives from the Sun (1361 W m-2), resulting in the right conditions for water vapor to condense and explain the detected clouds. In this study we observed nine transits of K2-18b using Hubble Space Telescope/WFC3 in order to achieve the necessary sensitivity to detect the water vapor, and we supplement this data set with Spitzer and K2 observations to obtain a broader wavelength coverage. While the thick hydrogen-dominated envelope we detect on K2-18b means that the planet is not a true Earth analog, our observations demonstrate that low-mass habitable-zone planets with the right conditions for liquid water are accessible with state-of-the-art telescopes. 2020-10-28T14:57:22Z 2020-10-28T14:57:22Z 2019-12 2019-09 2020-10-19T18:12:45Z Article http://purl.org/eprint/type/JournalArticle 2041-8213 2041-8205 https://hdl.handle.net/1721.1/128227 Benneke, Björn et al. "Water Vapor and Clouds on the Habitable-zone Sub-Neptune Exoplanet K2-18b." Astrophysical Journal Letters 887, 1 (December 2019): 887 © 2019 The American Astronomical Society en http://dx.doi.org/10.3847/2041-8213/AB59DC Astrophysical Journal Letters Creative Commons Attribution 3.0 unported license https://creativecommons.org/licenses/by/3.0/ application/pdf American Astronomical Society The American Astronomical Society |
| spellingShingle | Benneke, Björn Wong, Ian Piaulet, Caroline Knutson, Heather A Lothringer, Joshua Morley, Caroline V Gao, Peter Greene, Thomas P Dressing, Courtney Dragomir, Diana Howard, Andrew W McCullough, Peter R Kempton, Eliza M-R Fortney, Jonathan J Fraine, Jonathan Crossfield, Ian Jm Water Vapor and Clouds on the Habitable-zone Sub-Neptune Exoplanet K2-18b |
| title | Water Vapor and Clouds on the Habitable-zone Sub-Neptune Exoplanet K2-18b |
| title_full | Water Vapor and Clouds on the Habitable-zone Sub-Neptune Exoplanet K2-18b |
| title_fullStr | Water Vapor and Clouds on the Habitable-zone Sub-Neptune Exoplanet K2-18b |
| title_full_unstemmed | Water Vapor and Clouds on the Habitable-zone Sub-Neptune Exoplanet K2-18b |
| title_short | Water Vapor and Clouds on the Habitable-zone Sub-Neptune Exoplanet K2-18b |
| title_sort | water vapor and clouds on the habitable zone sub neptune exoplanet k2 18b |
| url | https://hdl.handle.net/1721.1/128227 |
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