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Revisiting KELT-19Ab, WASP-156b, and WASP-121b in the TESS Era

Yang, Fan and Chary, Ranga-Ram and Liu, Ji-Feng (2022) Revisiting KELT-19Ab, WASP-156b, and WASP-121b in the TESS Era. Astronomical Journal, 163 (2). Art. No. 42. ISSN 0004-6256. doi:10.3847/1538-3881/ac3b4e.

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We present a re-analysis of transit depths of KELT-19Ab, WASP-156b, and WASP-121b, including data from the Transiting Exoplanet Survey Satellite (TESS). The large ∼21″ TESS pixels and point-spread function result in significant contamination of the stellar flux by nearby objects. We use Gaia data to fit for and remove this contribution, providing general-purpose software for this correction. We find all three sources have a larger inclination, compared to earlier work. For WASP-121b, we find significantly smaller values (13.°5) of the inclination when using the 30 minute cadence data compared to the 2 minute cadence data. Using simulations, we demonstrate that the radius ratio of exoplanet to star (R_p/R_*) is biased small relative to data taken with a larger sampling interval although oversampling corrections mitigate the bias. This is particularly important for deriving subpercent transit differences between bands. We find the radius ratio of exoplanet to star (R_p/R_*) in the TESS band is 7.5σ smaller than previous work for KELT-19Ab, but consistent to within ∼2σ for WASP-156b and WASP-121b. The difference could be due to specific choices in the analysis, not necessarily due to the presence of atmospheric features. The result for KELT-19Ab possibly favors a haze-dominated atmosphere. We do not find evidence for the ∼0.95 μm water feature contaminating transit depths in the TESS band for these stars but show that with photometric precision of 500 ppm and with a sampling of about 200 observations across the entire transit, this feature could be detectable in a more narrow z-band.

Item Type:Article
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URLURL TypeDescription Paper
Yang, Fan0000-0002-6039-8212
Chary, Ranga-Ram0000-0001-7583-0621
Liu, Ji-Feng0000-0002-2874-2706
Additional Information:© 2022. The Author(s). Published by the American Astronomical. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2020 December 15; revised 2021 October 27; accepted 2021 November 17; published 2022 January 5. We are very grateful to the thoughtful comments by a referee which greatly improved the quality of results presented in this manuscript. This work made use of PyAstronomy and the NASA Exoplanet Archive. We would like to thank Jayesh M. Goyal for useful inputs and discussion and Caltech Optical Observatories for supporting the visit by the lead author. We also thank Hilke Schlichting for useful feedback on the manuscript. We sincerely thank Karen A. Collins for providing KELT-19Ab ground-based light curves. Fan Yang and Ji-Feng Liu acknowledge funding from the National Natural Science Foundation of China (NSFC.11988101), National Key Research and Development Program of China (No. 2016YFA0400800), and National Science Fund for Distinguished Young Scholars (No. 11425313).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Caltech Optical ObservatoriesUNSPECIFIED
National Natural Science Foundation of China11988101
National Key Research and Development Program of China2016YFA0400800
National Science Fund for Distinguished Young Scholars11425313
Subject Keywords:Exoplanet atmospheres; Exoplanet atmospheric composition; Exoplanet systems; Exoplanet astronomy
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Exoplanet atmospheres (487); Exoplanet atmospheric composition (2021); Exoplanet systems (484); Exoplanet astronomy (486)
Record Number:CaltechAUTHORS:20220114-264688000
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Official Citation:Fan Yang et al 2022 AJ 163 42
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112925
Deposited By: George Porter
Deposited On:18 Jan 2022 23:38
Last Modified:18 Jan 2022 23:38

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