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The Posttransit Tail of WASP-107b Observed at 10830 Å

Spake, J. J. and Oklopčić, A. and Hillenbrand, L. A. (2021) The Posttransit Tail of WASP-107b Observed at 10830 Å. Astronomical Journal, 162 (6). Art. No. 284. ISSN 0004-6256. doi:10.3847/1538-3881/ac178a.

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Understanding the effects of high-energy radiation and stellar winds on planetary atmospheres is vital for explaining the observed properties of close-in exoplanets. Observations of transiting exoplanets in the triplet of metastable helium lines at 10830 Å allow extended atmospheres and escape processes to be studied for individual planets. We observed one transit of WASP-107b with NIRSPEC on Keck at 10830 Å. Our observations, for the first time, had significant posttransit phase coverage, and we detected excess absorption for over an hour after fourth contact. The data can be explained by a comet-like tail extending out to ∼7 planet radii, which corresponds to roughly twice the Roche lobe radius of the planet. Planetary tails are expected based on three-dimensional simulations of escaping exoplanet atmospheres, particularly those including the interaction between the escaped material and strong stellar winds, and have been previously observed at 10830 Å in at least one other exoplanet. With both the largest midtransit absorption signal and the most extended tail observed at 10830 Å, WASP-107b remains a keystone exoplanet for atmospheric escape studies.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Spake, J. J.0000-0002-5547-3775
Oklopčić, A.0000-0002-9584-6476
Alternate Title:The post-transit tail of WASP-107b observed at 10830A
Additional Information:© 2021. The American Astronomical Society. Received 2021 March 23; revised 2021 July 19; accepted 2021 July 22; published 2021 December 2. We are extremely grateful to Carlos Alvarez and Greg Doppmann for their expert assistance with Keck/NIRSPEC operations, especially during the early postupgrade epoch of our observations, and to Emily Martin for helpful preobservation conversations concerning the upgraded instrument. We thank Trevor David, James Kirk, Ryan Rubenzahl, Michael Zhang, Fei Dai, Heather Knutson, and Romain Allart for helpful discussions. We also thank Lile Wang and Fei Dai for the model light curve. We thank the expert referee for helpful comments. A.O. gratefully acknowledges support from the Dutch Research Council NWO Veni grant. J.J.S. is supported by the Heising Simons 51 Pegasi b postdoctoral fellowship. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We were most fortunate to have the opportunity to conduct observations from this mountain. Facility: Keck:II (NIRSPEC). - Software: SciPy (Virtanen et al. 2020); NumPy (Van Der Walt et al. 2011); matplotlib (Hunter 2007); Astropy (Astropy Collaboration et al. 2013); and iSpec (Blanco-Cuaresma et al.2014).
Group:Astronomy Department
Funding AgencyGrant Number
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)UNSPECIFIED
Heising-Simons Foundation51 Pegasi b Fellowship
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:Exoplanets; Exoplanet astronomy; Extrasolar gaseous planets; Exoplanet atmospheres; Exoplanet atmospheric composition
Issue or Number:6
Classification Code:Unified Astronomy Thesaurus concepts: Exoplanets (498); Exoplanet astronomy (486); Extrasolar gaseous planets (2172); Exoplanet atmospheres (487); Exoplanet atmospheric composition (2021)
Record Number:CaltechAUTHORS:20211203-204701037
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Official Citation:J. J. Spake et al 2021 AJ 162 284
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112199
Deposited By: George Porter
Deposited On:06 Dec 2021 18:10
Last Modified:06 Dec 2021 18:10

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