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HST PanCET Program: A Cloudy Atmosphere for the Promising JWST Target WASP-101b

Wakeford, H. R. and Stevenson, K. B. and Lewis, N. K. and Sing, D. K. and López-Morales, M. and Marley, M. and Kataria, T. and Mandell, A. and Ballester, G. E. and Barstow, J. and Ben-Jaffel, L. and Bourrier, V. and Buchhave, L. A. and Ehrenreich, D. and Evans, T. Matthew and García Muñoz, A. and Henry, G. and Knutson, H. and Lavvas, P. and Lecavelier des Etangs, A. and Nikolov, N. and Sanz-Forcada, J. (2017) HST PanCET Program: A Cloudy Atmosphere for the Promising JWST Target WASP-101b. Astrophysical Journal Letters, 835 (1). Art. No. L12. ISSN 2041-8205. doi:10.3847/2041-8213/835/1/L12.

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We present results from the first observations of the Hubble Space Telescope (HST) Panchromatic Comparative Exoplanet Treasury program for WASP-101b, a highly inflated hot Jupiter and one of the community targets proposed for the James Webb Space Telescope (JWST) Early Release Science (ERS) program. From a single HST Wide Field Camera 3 observation, we find that the near-infrared transmission spectrum of WASP-101b contains no significant H2O absorption features and we rule out a clear atmosphere at 13σ. Therefore, WASP-101b is not an optimum target for a JWST ERS program aimed at observing strong molecular transmission features. We compare WASP-101b to the well-studied and nearly identical hot Jupiter WASP-31b. These twin planets show similar temperature–pressure profiles and atmospheric features in the near-infrared. We suggest exoplanets in the same parameter space as WASP-101b and WASP-31b will also exhibit cloudy transmission spectral features. For future HST exoplanet studies, our analysis also suggests that a lower count limit needs to be exceeded per pixel on the detector in order to avoid unwanted instrumental systematics.

Item Type:Article
Related URLs:
URLURL TypeDescription
Wakeford, H. R.0000-0003-4328-3867
Stevenson, K. B.0000-0002-7352-7941
Lewis, N. K.0000-0002-8507-1304
Sing, D. K.0000-0001-6050-7645
López-Morales, M.0000-0003-3204-8183
Marley, M.0000-0002-5251-2943
Kataria, T.0000-0003-3759-9080
Barstow, J.0000-0003-3726-5419
Bourrier, V.0000-0002-9148-034X
Buchhave, L. A.0000-0003-1605-5666
Ehrenreich, D.0000-0001-9704-5405
Evans, T. Matthew0000-0001-5442-1300
Knutson, H.0000-0002-0822-3095
Lecavelier des Etangs, A.0000-0002-5637-5253
Nikolov, N.0000-0002-6500-3574
Additional Information:© 2017 American Astronomical Society. Received 2016 December 9. Accepted 2017 January 3. Published 2017 January 20. This research has made use of NASA's Astrophysics Data System and components of the IDL astronomy library. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program GO-14767. H.R.W. acknowledges support by an appointment to the NASA Postdoctoral Program at Goddard Space Flight Center, administered by USRA through a contract with NASA. D.K.S., N.N., and T.E. acknowledge funding from the European Research Council under the European Unions Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement No. 336792. J.K.B. is supported by a Royal Astronomical Society Research Fellowship. D.E. acknowledges the financial support of the National Centre for Competence in Research "PlanetS" supported by the Swiss National Science Foundation (SNSF). L.B.-J., P.L., and A.L. acknowledge support from CNES (France) under project PACES. The authors would like to thank the referee for their careful examination of this Letter. Facility: HST (WFC3) - Hubble Space Telescope satellite.
Group:Astronomy Department
Funding AgencyGrant Number
NASANAS 5-26555
NASA Postdoctoral ProgramUNSPECIFIED
European Research Council (ERC)336792
Royal Astronomical SocietyUNSPECIFIED
Swiss National Science Foundation (SNSF)UNSPECIFIED
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Subject Keywords:planets and satellites: atmospheres; planets and satellites: individual (WASP-101b) ; techniques: spectroscopic
Issue or Number:1
Record Number:CaltechAUTHORS:20170131-073956256
Persistent URL:
Official Citation:H. R. Wakeford et al 2017 ApJL 835 L12
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73841
Deposited By: Ruth Sustaita
Deposited On:31 Jan 2017 16:01
Last Modified:11 Nov 2021 05:22

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