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Hubble Space Telescope hot Jupiter transmission spectral survey: a detection of Na and strong optical absorption in HAT-P-1b

Nikolov, N. and Sing, D. K. and Pont, F. and Burrows, A. S. and Fortney, J. J. and Ballester, G. E. and Evans, T. M. and Huitson, C. M. and Wakeford, H. R. and Wilson, P. A. and Aigrain, S. and Deming, D. and Gibson, N. P. and Henry, G. W. and Knutson, H. and Lecavelier des Etangs, A. and Showman, A. P. and Vidal-Madjar, A. and Zahnle, K. (2014) Hubble Space Telescope hot Jupiter transmission spectral survey: a detection of Na and strong optical absorption in HAT-P-1b. Monthly Notices of the Royal Astronomical Society, 437 (1). pp. 46-66. ISSN 0035-8711. doi:10.1093/mnras/stt1859.

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We present an optical to near-infrared transmission spectrum of the hot Jupiter HAT-P-1b, based on Hubble Space Telescope observations, covering the spectral regime from 0.29 to 1.027 μm with Space Telescope Imaging Spectrograph (STIS), which is coupled with a recent Wide Field Camera 3 (WFC3) transit (1.087 to 1.687 μm). We derive refined physical parameters of the HAT-P-1 system, including an improved orbital ephemeris. The transmission spectrum shows a strong absorption signature shortward of 0.55 μm, with a strong blueward slope into the near-ultraviolet. We detect atmospheric sodium absorption at a 3.3σ significance level, but find no evidence for the potassium feature. The red data imply a marginally flat spectrum with a tentative absorption enhancement at wavelength longer than ∼ 0.85 μm. The STIS and WFC3 spectra differ significantly in absolute radius level (4.3 ± 1.6 pressure scaleheights), implying strong optical absorption in the atmosphere of HAT-P-1b. The optical to near-infrared difference cannot be explained by stellar activity, as simultaneous stellar activity monitoring of the G0V HAT-P-1b host star and its identical companion show no significant activity that could explain the result. We compare the complete STIS and WFC3 transmission spectrum with theoretical atmospheric models which include haze, sodium and an extra optical absorber. We find that both an optical absorber and a supersolar sodium to water abundance ratio might be a scenario explaining the HAT-P-1b observations. Our results suggest that strong optical absorbers may be a dominant atmospheric feature in some hot Jupiter exoplanets.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Nikolov, N.0000-0002-6500-3574
Sing, D. K.0000-0001-6050-7645
Pont, F.0000-0003-0076-5444
Burrows, A. S.0000-0002-3099-5024
Fortney, J. J.0000-0002-9843-4354
Evans, T. M.0000-0001-5442-1300
Wakeford, H. R.0000-0003-4328-3867
Aigrain, S.0000-0003-1453-0574
Deming, D.0000-0001-5727-4094
Gibson, N. P.0000-0002-9308-2353
Henry, G. W.0000-0003-4155-8513
Knutson, H.0000-0002-0822-3095
Lecavelier des Etangs, A.0000-0002-5637-5253
Alternate Title:HST hot Jupiter Transmission Spectral Survey: A detection of Na and strong optical absorption in HAT-P-1b
Additional Information:© 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2013 September 30; Received 2013 September 30; in original form 2013 July 10. First published online: October 22, 2013. This work is based on observations with the NASA/ESA Hubble Space Telescope. We are grateful to the team at the STScI help desk for their roles in resolving technical issues with the STIS data processing pipeline. NN and DKS acknowledge support from STFC consolidated grant ST/J0016/1.CMH and PAW acknowledge a support from STFC grants. All US-based co-authors acknowledge support from the Space Telescope Science Institute under HST-GO-12473 grants to their respective institutions. The authors would like to acknowledge the anonymous referee for their useful comments
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)ST/J0016/1
Space Telescope Science InstituteUNSPECIFIED
Subject Keywords:techniques: spectroscopic; planets and satellites: individual: HAT-P-1b; stars: individual: HAT-P-1b
Issue or Number:1
Record Number:CaltechAUTHORS:20140122-093145219
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43465
Deposited By: Jason Perez
Deposited On:22 Jan 2014 23:08
Last Modified:10 Nov 2021 16:38

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