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Title: Clouds on the hot Jupiter HD189733b: Constraints from the reflection spectrum

The hot Jupiter HD 189733b is probably the best studied of the known extrasolar planets, with published transit and eclipse spectra covering the near UV to mid-IR range. Recent work on the transmission spectrum has shown clear evidence for the presence of clouds in its atmosphere, which significantly increases the model atmosphere parameter space that must be explored in order to fully characterize this planet. In this work, we apply the NEMESIS atmospheric retrieval code to the recently published HST/STIS reflection spectrum, and also to the dayside thermal emission spectrum in light of new Spitzer/IRAC measurements, as well as our own re-analysis of the HST/NICMOS data. We first use the STIS data to place some constraints on the nature of clouds on HD 189733b and explore solution degeneracy between different cloud properties and the abundance of Na in the atmosphere; as already noted in previous work, absorption due to Na plays a significant role in determining the shape of the reflection spectrum. We then perform a new retrieval of the temperature profile and abundances of H{sub 2}O, CO{sub 2}, CO, and CH{sub 4} from the dayside thermal emission spectrum. Finally, we investigate the effect of including cloud in the modelmore » on this retrieval process. We find that the current quality of data does not warrant the extra complexity introduced by including cloud in the model; however, future data are likely to be of sufficient resolution and signal-to-noise that a more complete model, including scattering particles, will be required.« less
Authors:
; ; ; ;  [1] ;  [2] ;  [3]
  1. Department of Physics, University of Oxford, Oxford (United Kingdom)
  2. Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich (Switzerland)
  3. European Southern Observatory, D-85748 Garching bei München (Germany)
Publication Date:
OSTI Identifier:
22356909
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 786; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; CARBON DIOXIDE; CARBON MONOXIDE; DATA ANALYSIS; ECLIPSE; EMISSION SPECTRA; JUPITER PLANET; METHANE; RADIANT HEAT TRANSFER; REFLECTION; RESOLUTION; SATELLITE ATMOSPHERES; SCATTERING; SPACE; TRANSMISSION; VISIBLE RADIATION