Two Earth-sized planets orbiting Kepler-20
Article
Article Title | Two Earth-sized planets orbiting Kepler-20 |
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ERA Journal ID | 17479 |
Article Category | Article |
Authors | Fressin, Francois (Author), Torres, Guillermo (Author), Rowe, Jason F. (Author), Charbonneau, David (Author), Rogers, Leslie A. (Author), Ballard, Sarah (Author), Batalha, Natalie M. (Author), Borucki, William J. (Author), Bryson, Stephen T. (Author), Buchhave, Lars A. (Author), Ciardi, David R. (Author), Desert, Jean Michel (Author), Dressing, Courtney D. (Author), Fabrycky, Daniel C. (Author), Ford, Eric B. (Author), Gautier, Thomas N. (Author), Henze, Christopher E. (Author), Holman, Matthew J. (Author), Howard, Andrew (Author), Howell, Steve B. (Author), Jenkins, Jon M. (Author), Koch, David G. (Author), Latham, David W. (Author), Lissauer, Jack J. (Author), Marcy, Geoffrey W. (Author), Quinn, Samuel N. (Author), Ragozzine, Darin (Author), Sasselov, Dimitar D. (Author), Seager, Sara (Author), Barclay, Thomas (Author), Mullally, Fergal (Author), Seader, Shawn E. (Author), Still, Martin (Author), Twicken, Joseph D. (Author), Thompson, Susan E. (Author) and Uddin, Kamal (Author) |
Journal Title | Nature |
Journal Citation | 482 (7384), pp. 195-198 |
Number of Pages | 4 |
Year | 2012 |
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/nature10780 |
Web Address (URL) | http://www.nature.com/nature/journal/v482/n7384/full/nature10780.html |
Abstract | Since the discovery of the first extrasolar giant planets around Sun-like stars, evolving observational capabilities have brought us closer to the detection of true Earth analogues. The size of an exoplanet can be determined when it periodically passes in front of (transits) its parent star, causing a decrease in starlight proportional to its radius. The smallest exoplanet hitherto discovered has a radius 1.42 times that of the Earth's radius (R ⊕ •), and hence has 2.9 times its volume. Here we report the discovery of two planets, one Earth-sized (1.03R ⊕ •) and the other smaller than the Earth (0.87R ⊕ •), orbiting the star Kepler-20, which is already known to host three other, larger, transiting planets. The gravitational pull of the new planets on the parent star is too small to measure with current instrumentation. We apply a statistical method to show that the likelihood of the planetary interpretation of the transit signals is more than three orders of magnitude larger than that of the alternative hypothesis that the signals result from an eclipsing binary star. Theoretical considerations imply that these planets are rocky, with a composition of iron and silicate. The outer planet could have developed a thick water vapour atmosphere. |
Keywords | extrasolar planets; exoplanets; Kepler; photometry; spectroscopy; radial velocity |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
519999. Other physical sciences not elsewhere classified | |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Center for Astrophysics Harvard and Smithsonian, United States |
NASA Ames Research Center, United States | |
Massachusetts Institute of Technology, United States | |
Center for Astrophysics Harvard and Smithsonian, United States | |
San Jose University, United States | |
University of Copenhagen, Denmark | |
National Aeronautics and Space Administration (NASA), United States | |
University of California, United States | |
University of Florida, United States | |
California Institute of Technology (Caltech), United States | |
SETI Institute, United States | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q432q/two-earth-sized-planets-orbiting-kepler-20
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