LOW STELLAR OBLIQUITIES IN COMPACT MULTIPLANET SYSTEMS
We measure the sky-projected stellar obliquities (λ) in the multiple-transiting planetary systems KOI-94 and Kepler-25, using the Rossiter-McLaughlin effect. In both cases, the host stars are well aligned with the orbital planes of the planets. For KOI-94 we find λ = –11° ± 11°, confirming a recent...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | en_US |
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IOP Publishing
2014
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| Online Access: | http://hdl.handle.net/1721.1/89225 https://orcid.org/0000-0002-4265-047X |
| _version_ | 1811088581364547584 |
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| author | Albrecht, Simon H. Marcy, Geoffrey W. Howard, Andrew W. Isaacson, Howard Johnson, John Asher Winn, Joshua Nathan |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Albrecht, Simon H. Marcy, Geoffrey W. Howard, Andrew W. Isaacson, Howard Johnson, John Asher Winn, Joshua Nathan |
| author_sort | Albrecht, Simon H. |
| collection | MIT |
| description | We measure the sky-projected stellar obliquities (λ) in the multiple-transiting planetary systems KOI-94 and Kepler-25, using the Rossiter-McLaughlin effect. In both cases, the host stars are well aligned with the orbital planes of the planets. For KOI-94 we find λ = –11° ± 11°, confirming a recent result by Hirano and coworkers. Kepler-25 was a more challenging case, because the transit depth is unusually small (0.13%). To obtain the obliquity, it was necessary to use prior knowledge of the star's projected rotation rate and apply two different analysis methods to independent wavelength regions of the spectra. The two methods gave consistent results, λ = 7° ± 8° and –0[° over .]5 ± 5[° over .]7. There are now a total of five obliquity measurements for host stars of systems of multiple-transiting planets, all of which are consistent with spin-orbit alignment. This alignment is unlikely to be the result of tidal interactions because of the relatively large orbital distances and low planetary masses in the systems. In this respect, the multiplanet host stars differ from hot-Jupiter host stars, which commonly have large spin-orbit misalignments whenever tidal interactions are weak. In particular, the weak-tide subset of hot-Jupiter hosts has obliquities consistent with an isotropic distribution (p = 0.6), but the multiplanet hosts are incompatible with such a distribution (p ~ 10[superscript –6]). This suggests that high obliquities are confined to hot-Jupiter systems, and provides further evidence that hot-Jupiter formation involves processes that tilt the planetary orbit. |
| first_indexed | 2024-09-23T14:04:18Z |
| format | Article |
| id | mit-1721.1/89225 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T14:04:18Z |
| publishDate | 2014 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/892252022-09-28T18:09:41Z LOW STELLAR OBLIQUITIES IN COMPACT MULTIPLANET SYSTEMS Albrecht, Simon H. Marcy, Geoffrey W. Howard, Andrew W. Isaacson, Howard Johnson, John Asher Winn, Joshua Nathan Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Albrecht, Simon H. Winn, Joshua Nathan We measure the sky-projected stellar obliquities (λ) in the multiple-transiting planetary systems KOI-94 and Kepler-25, using the Rossiter-McLaughlin effect. In both cases, the host stars are well aligned with the orbital planes of the planets. For KOI-94 we find λ = –11° ± 11°, confirming a recent result by Hirano and coworkers. Kepler-25 was a more challenging case, because the transit depth is unusually small (0.13%). To obtain the obliquity, it was necessary to use prior knowledge of the star's projected rotation rate and apply two different analysis methods to independent wavelength regions of the spectra. The two methods gave consistent results, λ = 7° ± 8° and –0[° over .]5 ± 5[° over .]7. There are now a total of five obliquity measurements for host stars of systems of multiple-transiting planets, all of which are consistent with spin-orbit alignment. This alignment is unlikely to be the result of tidal interactions because of the relatively large orbital distances and low planetary masses in the systems. In this respect, the multiplanet host stars differ from hot-Jupiter host stars, which commonly have large spin-orbit misalignments whenever tidal interactions are weak. In particular, the weak-tide subset of hot-Jupiter hosts has obliquities consistent with an isotropic distribution (p = 0.6), but the multiplanet hosts are incompatible with such a distribution (p ~ 10[superscript –6]). This suggests that high obliquities are confined to hot-Jupiter systems, and provides further evidence that hot-Jupiter formation involves processes that tilt the planetary orbit. United States. National Aeronautics and Space Administration (Origins Award NNX09AB33G) National Science Foundation (U.S.) (Grant 1108595) 2014-09-09T14:59:18Z 2014-09-09T14:59:18Z 2013-06 2013-02 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/89225 Albrecht, Simon, Joshua N. Winn, Geoffrey W. Marcy, Andrew W. Howard, Howard Isaacson, and John A. Johnson. “LOW STELLAR OBLIQUITIES IN COMPACT MULTIPLANET SYSTEMS.” The Astrophysical Journal 771, no. 1 (June 10, 2013): 11. https://orcid.org/0000-0002-4265-047X en_US http://dx.doi.org/10.1088/0004-637X/771/1/11 The Astrophysical Journal Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf IOP Publishing arXiv |
| spellingShingle | Albrecht, Simon H. Marcy, Geoffrey W. Howard, Andrew W. Isaacson, Howard Johnson, John Asher Winn, Joshua Nathan LOW STELLAR OBLIQUITIES IN COMPACT MULTIPLANET SYSTEMS |
| title | LOW STELLAR OBLIQUITIES IN COMPACT MULTIPLANET SYSTEMS |
| title_full | LOW STELLAR OBLIQUITIES IN COMPACT MULTIPLANET SYSTEMS |
| title_fullStr | LOW STELLAR OBLIQUITIES IN COMPACT MULTIPLANET SYSTEMS |
| title_full_unstemmed | LOW STELLAR OBLIQUITIES IN COMPACT MULTIPLANET SYSTEMS |
| title_short | LOW STELLAR OBLIQUITIES IN COMPACT MULTIPLANET SYSTEMS |
| title_sort | low stellar obliquities in compact multiplanet systems |
| url | http://hdl.handle.net/1721.1/89225 https://orcid.org/0000-0002-4265-047X |
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