3.6 AND 4.5 mu m SPITZER PHASE CURVES OF THE HIGHLY IRRADIATED HOT JUPITERS WASP-19b AND HAT-P-7b
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3.6 AND 4.5 mu m SPITZER PHASE CURVES OF THE HIGHLY IRRADIATED HOT JUPITERS WASP-19b AND HAT-P-7b

  • Author(s): Wong, Ian
  • Knutson, Heather A
  • Kataria, Tiffany
  • Lewis, Nikole K
  • Burrows, Adam
  • Fortney, Jonathan J
  • Schwartz, Joel
  • Shporer, Avi
  • Agol, Eric
  • Cowan, Nicolas B
  • Deming, Drake
  • Desert, Jean-Michel
  • Fulton, Benjamin J
  • Howard, Andrew W
  • Langton, Jonathan
  • Laughlin, Gregory
  • Showman, Adam P
  • Todorov, Kamen
  • et al.

Published Web Location

https://arxiv.org/abs/1512.09342
No data is associated with this publication.
Abstract

We analyze full-orbit phase curve observations of the transiting hot Jupiters WASP-19b and HAT-P-7b at 3.6 and 4.5 $\mu$m obtained using the Spitzer Space Telescope. For WASP-19b, we measure secondary eclipse depths of $0.485\%\pm 0.024\%$ and $0.584\%\pm 0.029\%$ at 3.6 and 4.5 $\mu$m, which are consistent with a single blackbody with effective temperature $2372 \pm 60$ K. The measured 3.6 and 4.5 $\mu$m secondary eclipse depths for HAT-P-7b are $0.156\%\pm 0.009\%$ and $0.190\%\pm 0.006\%$, which are well-described by a single blackbody with effective temperature $2667\pm 57$ K. Comparing the phase curves to the predictions of one-dimensional and three-dimensional atmospheric models, we find that WASP-19b's dayside emission is consistent with a model atmosphere with no dayside thermal inversion and moderately efficient day-night circulation. We also detect an eastward-shifted hotspot, suggesting the presence of a superrotating equatorial jet. In contrast, HAT-P-7b's dayside emission suggests a dayside thermal inversion and relatively inefficient day-night circulation; no hotspot shift is detected. For both planets, these same models do not agree with the measured nightside emission. The discrepancies in the model-data comparisons for WASP-19b might be explained by high-altitude silicate clouds on the nightside and/or high atmospheric metallicity, while the very low 3.6 $\mu$m nightside planetary brightness for HAT-P-7b may be indicative of an enhanced global C/O ratio. We compute Bond albedos of 0 ($<0.08$ at $1\sigma$) and $0.38\pm 0.06$ for WASP-19b and HAT-P-7b, respectively. In the context of other planets with thermal phase curve measurements, we show that WASP-19b and HAT-P-7b fit the general trend of decreasing day-night heat recirculation with increasing irradiation.

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