TESS full orbital phase curve of the WASP-18b system

We present a visible-light full orbital phase curve of the transiting planet WASP-18b measured by the TESS mission. The phase curve includes the transit, secondary eclipse, and sinusoidal modulations across the orbital phase shaped by the planet's atmospheric characteristics and the star-planet...

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Main Authors: Shporer, Avi, Wong, Ian, Huang, Chelsea, Daylan, Tansu, Guenther, Maximilian N., Ricker, George R., Vanderspek, Roland K., Seager, Sara, Glidden, Ana Rose Walsh, Haworth, Kari
Other Authors: Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Format: Article
Language:English
Published: American Astronomical Society 2020
Online Access:https://hdl.handle.net/1721.1/124718
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author Shporer, Avi
Wong, Ian
Huang, Chelsea
Daylan, Tansu
Guenther, Maximilian N.
Ricker, George R.
Vanderspek, Roland K.
Seager, Sara
Glidden, Ana Rose Walsh
Haworth, Kari
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
Shporer, Avi
Wong, Ian
Huang, Chelsea
Daylan, Tansu
Guenther, Maximilian N.
Ricker, George R.
Vanderspek, Roland K.
Seager, Sara
Glidden, Ana Rose Walsh
Haworth, Kari
author_sort Shporer, Avi
collection MIT
description We present a visible-light full orbital phase curve of the transiting planet WASP-18b measured by the TESS mission. The phase curve includes the transit, secondary eclipse, and sinusoidal modulations across the orbital phase shaped by the planet's atmospheric characteristics and the star-planet gravitational interaction. We measure the beaming (Doppler boosting) and tidal ellipsoidal distortion phase modulations and show that the amplitudes of both agree with theoretical expectations. We find that the light from the planet's dayside hemisphere occulted during secondary eclipse, with a relative brightness of 341-18+17 ppm, is dominated by thermal emission, leading to an upper limit on the geometric albedo in the TESS band of 0.048 (2σ). We also detect the phase modulation due to the planet's atmosphere longitudinal brightness distribution. We find that its maximum is well aligned with the substellar point to within 2.°9 (2σ). We do not detect light from the planet's nightside hemisphere, with an upper limit of 43 ppm (2σ), which is 13% of the dayside brightness. The low albedo, lack of atmospheric phase shift, and inefficient heat distribution from the day to night hemispheres that we deduce from our analysis are consistent with theoretical expectations and similar findings for other strongly irradiated gas giant planets. This work demonstrates the potential of TESS data for studying the full orbital phase curves of transiting systems. Finally, we complement our study by looking for transit timing variations (TTVs) in the TESS data combined with previously published transit times, although we do not find a statistically significant TTV signal. ©2019
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spelling mit-1721.1/1247182022-09-26T16:03:01Z TESS full orbital phase curve of the WASP-18b system Shporer, Avi Wong, Ian Huang, Chelsea Daylan, Tansu Guenther, Maximilian N. Ricker, George R. Vanderspek, Roland K. Seager, Sara Glidden, Ana Rose Walsh Haworth, Kari Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences MIT Kavli Institute for Astrophysics and Space Research We present a visible-light full orbital phase curve of the transiting planet WASP-18b measured by the TESS mission. The phase curve includes the transit, secondary eclipse, and sinusoidal modulations across the orbital phase shaped by the planet's atmospheric characteristics and the star-planet gravitational interaction. We measure the beaming (Doppler boosting) and tidal ellipsoidal distortion phase modulations and show that the amplitudes of both agree with theoretical expectations. We find that the light from the planet's dayside hemisphere occulted during secondary eclipse, with a relative brightness of 341-18+17 ppm, is dominated by thermal emission, leading to an upper limit on the geometric albedo in the TESS band of 0.048 (2σ). We also detect the phase modulation due to the planet's atmosphere longitudinal brightness distribution. We find that its maximum is well aligned with the substellar point to within 2.°9 (2σ). We do not detect light from the planet's nightside hemisphere, with an upper limit of 43 ppm (2σ), which is 13% of the dayside brightness. The low albedo, lack of atmospheric phase shift, and inefficient heat distribution from the day to night hemispheres that we deduce from our analysis are consistent with theoretical expectations and similar findings for other strongly irradiated gas giant planets. This work demonstrates the potential of TESS data for studying the full orbital phase curves of transiting systems. Finally, we complement our study by looking for transit timing variations (TTVs) in the TESS data combined with previously published transit times, although we do not find a statistically significant TTV signal. ©2019 2020-04-17T15:01:28Z 2020-04-17T15:01:28Z 2019-05 2018-11 2020-04-09T16:27:07Z Article http://purl.org/eprint/type/JournalArticle 1538-3881 https://hdl.handle.net/1721.1/124718 Shporer, Avi, et al., "TESS full orbital phase curve of the WASP-18b system." Astronomical journal 157, 5 (May 2019): no. 178 doi 10.3847/1538-3881/ab0f96 ©2019 Author(s) en 10.3847/1538-3881/ab0f96 Astronomical journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Astronomical Society The American Astronomical Society
spellingShingle Shporer, Avi
Wong, Ian
Huang, Chelsea
Daylan, Tansu
Guenther, Maximilian N.
Ricker, George R.
Vanderspek, Roland K.
Seager, Sara
Glidden, Ana Rose Walsh
Haworth, Kari
TESS full orbital phase curve of the WASP-18b system
title TESS full orbital phase curve of the WASP-18b system
title_full TESS full orbital phase curve of the WASP-18b system
title_fullStr TESS full orbital phase curve of the WASP-18b system
title_full_unstemmed TESS full orbital phase curve of the WASP-18b system
title_short TESS full orbital phase curve of the WASP-18b system
title_sort tess full orbital phase curve of the wasp 18b system
url https://hdl.handle.net/1721.1/124718
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