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Non-detection of Contamination by Stellar Activity in the Spitzer Transit Light Curves of TRAPPIST-1

Morris, Brett M. and Agol, Eric and Hebb, Leslie and Hawley, Suzanne L. and Gillon, Michaël and Ducrot, Elsa and Delrez, Laetitia and Ingalls, James and Demory, Brice-Olivier (2018) Non-detection of Contamination by Stellar Activity in the Spitzer Transit Light Curves of TRAPPIST-1. Astrophysical Journal Letters, 863 (2). Art. No. L32. ISSN 2041-8213. doi:10.3847/2041-8213/aad8aa.

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We apply the transit light curve self-contamination technique of Morris et al. to search for the effect of stellar activity on the transits of the ultracool dwarf TRAPPIST-1 with 2018 Spitzer photometry. The self-contamination method fits the transit light curves of planets orbiting spotted stars, allowing the host star to be a source of contaminating positive or negative flux that influences the transit depths but not the ingress/egress durations. We find that none of the planets show statistically significant evidence for self-contamination by bright or dark regions of the stellar photosphere. However, we show that small-scale magnetic activity, analogous in size to the smallest sunspots, could still be lurking undetected in the transit photometry.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Morris, Brett M.0000-0003-2528-3409
Agol, Eric0000-0002-0802-9145
Hebb, Leslie0000-0003-1263-8637
Hawley, Suzanne L.0000-0002-6629-4182
Gillon, Michaël0000-0003-1462-7739
Delrez, Laetitia0000-0001-6108-4808
Ingalls, James0000-0003-4714-1364
Demory, Brice-Olivier0000-0002-9355-5165
Additional Information:© 2018 The American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 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 2018 July 20; revised 2018 August 7; accepted 2018 August 7; published 2018 August 17. We are grateful for the greater Spitzer TRAPPIST analysis team, without whom this analysis would not have been possible: Artem Burdanov, Valerie Van Grootel, Didier Queloz, Amaury Triaud, Julien de Wit, Adam Burgasser, Sean Carey, Sue Lederer, Emeline Bolmont, Jeremy Leconte, Sean Raymond, and Franck Selsis. L.D. acknowledges support from the Simons Foundation (PI: Queloz, grant number 327127) and the Gruber Foundation Fellowship. M.G. is a F.R.S.-FNRS Senior Research Associate. The research leading to these results has received funding from the European Research Council under the FP/2007-2013 ERC grant agreement No. 336480, from the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation, and from the Balzan Foundation. E.A. acknowledges NSF grant AST-1615315, NASA grant NNX14AK26G and from the NASA Astrobiology Institute's Virtual Planetary Laboratory Lead Team, funded through the NASA Astrobiology Institute under solicitation NNH12ZDA002C and Cooperative Agreement Number NNA13AA93A. Facility: Spitzer - Spitzer Space Telescope satellite. Software: astropy (The Astropy Collaboration et al. 2018), emcee, (Foreman-Mackey et al. 2013), ipython (Pérez & Granger 2007), numpy (Van Der Walt et al. 2011), scipy (Jones et al. 2001), matplotlib (Hunter 2007), robin (Morris et al. 2018b).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Simons Foundation327127
Gruber FoundationUNSPECIFIED
Fonds de la Recherche Scientifique (FNRS)UNSPECIFIED
European Research Council (ERC)336480
Australian Research CouncilUNSPECIFIED
Wallonia-Brussels FederationUNSPECIFIED
International Balzan Prize FoundationUNSPECIFIED
Subject Keywords:planets and satellites: fundamental parameters – planets and satellites: terrestrial planets – stars: activity – stars: late-type – stars: magnetic field
Issue or Number:2
Record Number:CaltechAUTHORS:20180817-105312319
Persistent URL:
Official Citation:Brett M. Morris et al 2018 ApJL 863 L32
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:88926
Deposited By: Tony Diaz
Deposited On:17 Aug 2018 18:29
Last Modified:16 Nov 2021 00:30

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