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Into the UV: The Atmosphere of the Hot Jupiter HAT-P-41b Revealed

Lewis, N. K. and Wakeford, H. R. and MacDonald, R. J. and Goyal, J. M. and Sing, D. K. and Barstow, J. and Powell, D. and Kataria, T. and Mishra, I. and Marley, M. S. and Batalha, N. E. and Moses, J. I. and Gao, P. and Wilson, T. J. and Chubb, K. L. and Mikal-Evans, T. and Nikolov, N. and Pirzkal, N. and Spake, J. J. and Stevenson, K. B. and Valenti, J. and Zhang, X. (2020) Into the UV: The Atmosphere of the Hot Jupiter HAT-P-41b Revealed. Astrophysical Journal Letters, 902 (1). Art. No. L19. ISSN 2041-8213.

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For solar system objects, ultraviolet spectroscopy has been critical in identifying sources of stratospheric heating and measuring the abundances of a variety of hydrocarbon and sulfur-bearing species, produced via photochemical mechanisms, as well as oxygen and ozone. To date, fewer than 20 exoplanets have been probed in this critical wavelength range (0.2–0.4 μm). Here we use data from Hubble's newly implemented WFC3 UVIS G280 grism to probe the atmosphere of the hot Jupiter HAT-P-41b in the ultraviolet through optical in combination with observations at infrared wavelengths. We analyze and interpret HAT-P-41b's 0.2–5.0 μm transmission spectrum using a broad range of methodologies including multiple treatments of data systematics as well as comparisons with atmospheric forward, cloud microphysical, and multiple atmospheric retrieval models. Although some analysis and interpretation methods favor the presence of clouds or potentially a combination of Na, VO, AlO, and CrH to explain the ultraviolet through optical portions of HAT-P-41b's transmission spectrum, we find that the presence of a significant H⁻ opacity provides the most robust explanation. We obtain a constraint for the abundance of H⁻, log(H⁻) = -8.65 ± 0.62, in HAT-P-41b's atmosphere, which is several orders of magnitude larger than predictions from equilibrium chemistry for a ~1700–1950 K hot Jupiter. We show that a combination of photochemical and collisional processes on hot hydrogen-dominated exoplanets can readily supply the necessary amount of H− and suggest that such processes are at work in HAT-P-41b and the atmospheres of many other hot Jupiters.

Item Type:Article
Related URLs:
URLURL TypeDescription
Lewis, N. K.0000-0002-8507-1304
Wakeford, H. R.0000-0003-4328-3867
MacDonald, R. J.0000-0003-4816-3469
Goyal, J. M.0000-0002-8515-7204
Sing, D. K.0000-0001-6050-7645
Barstow, J.0000-0003-3726-5419
Powell, D.0000-0002-4250-0957
Kataria, T.0000-0003-3759-9080
Mishra, I.0000-0001-6092-7674
Marley, M. S.0000-0002-5251-2943
Batalha, N. E.0000-0003-1240-6844
Moses, J. I.0000-0002-8837-0035
Gao, P.0000-0002-8518-9601
Wilson, T. J.0000-0001-6352-9735
Chubb, K. L.0000-0002-4552-4559
Mikal-Evans, T.0000-0001-5442-1300
Nikolov, N.0000-0002-6500-3574
Pirzkal, N.0000-0003-3382-5941
Stevenson, K. B.0000-0002-7352-7941
Valenti, J.0000-0003-3305-6281
Additional Information:© 2020 The American Astronomical Society. Received 2020 March 13; revised 2020 September 7; accepted 2020 September 9; published 2020 October 8. This research is based on observations made with the NASA/ESA Hubble Space Telescope obtained from 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 programs GO-15288 and GO-14767. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. These observations are associated with program 13044. We thank Patrick Irwin for the use of NEMESIS, and Jake Taylor for assistance with the inclusion of H− opacity within the NEMESIS forward model. Software: IDL Astronomy user's library (Landsman 1995), NumPy (Oliphant 2006), SciPy (Virtanen et al. 2019), MatPlotLib (Caswell et al. 2019), AstroPy (Astropy Collaboration et al. 2018), Photutils (Bradley et al. 2019), MultiNest (Feroz & Hobson 2008; Feroz et al. 2009, 2019), PyMultiNest (Buchner et al. 2014), dynesty (Speagle 2020), ATMO (Amundsen et al. 2014; Tremblin et al. 2015, 2016; Wakeford et al. 2017; Goyal et al. 2018), NEMESIS (Irwin et al. 2008; Barstow et al. 2017), POSEIDON (MacDonald & Madhusudhan 2017). Facilities: HST(WFC3) - Hubble Space Telescope satellite, Spitzer(IRAC). -
Funding AgencyGrant Number
NASANAS 5-26555
Subject Keywords:Exoplanet atmospheres ; Observational astronomy ; Exoplanet atmospheric composition ; Spectroscopy
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Exoplanet atmospheres (487); Observational astronomy (1145); Exoplanet atmospheric composition (2021); Spectroscopy (1558)
Record Number:CaltechAUTHORS:20201012-132945049
Persistent URL:
Official Citation:N. K. Lewis et al 2020 ApJL 902 L19
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105986
Deposited By: Tony Diaz
Deposited On:12 Oct 2020 20:46
Last Modified:12 Oct 2020 20:46

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