THE STELLAR OBLIQUITY AND THE LONG-PERIOD PLANET IN THE HAT-P-17 EXOPLANETARY SYSTEM
We present the measured projected obliquity—the sky-projected angle between the stellar spin axis and orbital angular momentum—of the inner planet of the HAT-P-17 multi-planet system. We measure the sky-projected obliquity of the star to be $\lambda =19^{+14}_{-16}$ deg by modeling the Rossiter-McLa...
| Main Authors: | , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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Institute of Physics Publishing/American Astronomical Society
2014
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| Online Access: | http://hdl.handle.net/1721.1/88625 https://orcid.org/0000-0002-4265-047X |
| _version_ | 1826211650937552896 |
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| author | Fulton, Benjamin J. Howard, Andrew W. Winn, Joshua Nathan Albrecht, Simon H. Marcy, Geoffrey W. Crepp, Justin R. Bakos, Gaspar A. Johnson, John Asher Hartman, Joel D. Isaacson, Howard Knutson, Heather A. Zhao, Ming |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Fulton, Benjamin J. Howard, Andrew W. Winn, Joshua Nathan Albrecht, Simon H. Marcy, Geoffrey W. Crepp, Justin R. Bakos, Gaspar A. Johnson, John Asher Hartman, Joel D. Isaacson, Howard Knutson, Heather A. Zhao, Ming |
| author_sort | Fulton, Benjamin J. |
| collection | MIT |
| description | We present the measured projected obliquity—the sky-projected angle between the stellar spin axis and orbital angular momentum—of the inner planet of the HAT-P-17 multi-planet system. We measure the sky-projected obliquity of the star to be $\lambda =19^{+14}_{-16}$ deg by modeling the Rossiter-McLaughlin effect in Keck/HIRES radial velocities (RVs). The anomalous RV time series shows an asymmetry relative to the midtransit time, ordinarily suggesting a nonzero obliquity—but in this case at least part of the asymmetry may be due to the convective blueshift, increasing the uncertainty in the determination of λ. We employ the semi-analytical approach of Hirano et al. that includes the effects of macroturbulence, instrumental broadening, and convective blueshift to accurately model the anomaly in the net RV caused by the planet eclipsing part of the rotating star. Obliquity measurements are an important tool for testing theories of planet formation and migration. To date, the measured obliquities of ~50 Jovian planets span the full range, from prograde to retrograde, with planets orbiting cool stars preferentially showing alignment of stellar spins and planetary orbits. Our results are consistent with this pattern emerging from tidal interactions in the convective envelopes of cool stars and close-in planets. In addition, our 1.8 yr of new RVs for this system show that the orbit of the outer planet is more poorly constrained than previously thought, with an orbital period now in the range of 10-36 yr. |
| first_indexed | 2024-09-23T15:09:21Z |
| format | Article |
| id | mit-1721.1/88625 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T15:09:21Z |
| publishDate | 2014 |
| publisher | Institute of Physics Publishing/American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/886252022-09-29T13:01:26Z THE STELLAR OBLIQUITY AND THE LONG-PERIOD PLANET IN THE HAT-P-17 EXOPLANETARY SYSTEM Fulton, Benjamin J. Howard, Andrew W. Winn, Joshua Nathan Albrecht, Simon H. Marcy, Geoffrey W. Crepp, Justin R. Bakos, Gaspar A. Johnson, John Asher Hartman, Joel D. Isaacson, Howard Knutson, Heather A. Zhao, Ming Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Albrecht, Simon H. Winn, Joshua Nathan We present the measured projected obliquity—the sky-projected angle between the stellar spin axis and orbital angular momentum—of the inner planet of the HAT-P-17 multi-planet system. We measure the sky-projected obliquity of the star to be $\lambda =19^{+14}_{-16}$ deg by modeling the Rossiter-McLaughlin effect in Keck/HIRES radial velocities (RVs). The anomalous RV time series shows an asymmetry relative to the midtransit time, ordinarily suggesting a nonzero obliquity—but in this case at least part of the asymmetry may be due to the convective blueshift, increasing the uncertainty in the determination of λ. We employ the semi-analytical approach of Hirano et al. that includes the effects of macroturbulence, instrumental broadening, and convective blueshift to accurately model the anomaly in the net RV caused by the planet eclipsing part of the rotating star. Obliquity measurements are an important tool for testing theories of planet formation and migration. To date, the measured obliquities of ~50 Jovian planets span the full range, from prograde to retrograde, with planets orbiting cool stars preferentially showing alignment of stellar spins and planetary orbits. Our results are consistent with this pattern emerging from tidal interactions in the convective envelopes of cool stars and close-in planets. In addition, our 1.8 yr of new RVs for this system show that the orbit of the outer planet is more poorly constrained than previously thought, with an orbital period now in the range of 10-36 yr. 2014-08-08T17:18:22Z 2014-08-08T17:18:22Z 2013-08 2013-01 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/88625 Fulton, Benjamin J., Andrew W. Howard, Joshua N. Winn, Simon Albrecht, Geoffrey W. Marcy, Justin R. Crepp, Gaspar A. Bakos, et al. “The Stellar Obliquity and the Long-period Planet in the HAT-P-17 Exoplanetary System.” The Astrophysical Journal 772, no. 2 (July 9, 2013): 80. https://orcid.org/0000-0002-4265-047X en_US http://dx.doi.org/10.1088/0004-637X/772/2/80 The Astrophysical Journal Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Institute of Physics Publishing/American Astronomical Society arXiv |
| spellingShingle | Fulton, Benjamin J. Howard, Andrew W. Winn, Joshua Nathan Albrecht, Simon H. Marcy, Geoffrey W. Crepp, Justin R. Bakos, Gaspar A. Johnson, John Asher Hartman, Joel D. Isaacson, Howard Knutson, Heather A. Zhao, Ming THE STELLAR OBLIQUITY AND THE LONG-PERIOD PLANET IN THE HAT-P-17 EXOPLANETARY SYSTEM |
| title | THE STELLAR OBLIQUITY AND THE LONG-PERIOD PLANET IN THE HAT-P-17 EXOPLANETARY SYSTEM |
| title_full | THE STELLAR OBLIQUITY AND THE LONG-PERIOD PLANET IN THE HAT-P-17 EXOPLANETARY SYSTEM |
| title_fullStr | THE STELLAR OBLIQUITY AND THE LONG-PERIOD PLANET IN THE HAT-P-17 EXOPLANETARY SYSTEM |
| title_full_unstemmed | THE STELLAR OBLIQUITY AND THE LONG-PERIOD PLANET IN THE HAT-P-17 EXOPLANETARY SYSTEM |
| title_short | THE STELLAR OBLIQUITY AND THE LONG-PERIOD PLANET IN THE HAT-P-17 EXOPLANETARY SYSTEM |
| title_sort | stellar obliquity and the long period planet in the hat p 17 exoplanetary system |
| url | http://hdl.handle.net/1721.1/88625 https://orcid.org/0000-0002-4265-047X |
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