3.6 and 4.5 μm Spitzer phase curves of the highly irradiated hot jupiters WASP-19b and HAT-P-7b
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)
- Astrophysics Group, School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)
- Space Telescope Science Institute, Baltimore, MD 21218 (United States)
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
- Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95604 (United States)
- Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States)
- Department of Astronomy, University of Washington, Seattle, WA 98195 (United States)
- Department of Physics, McGill University, 3600 rue University, Montreal, QC, H3A 2T8 (Canada)
- Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)
- Department of Astrophysical and Planetary Science, University of Colorado, Boulder, CO 80309 (United States)
- Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)
- Department of Physics, Principia College, Elsah, IL 62028 (United States)
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)
- Institute for Astronomy, ETH Zürich, 8093 Zürich (Switzerland)
We analyze full-orbit phase curve observations of the transiting hot Jupiters WASP-19b and HAT-P-7b at 3.6 and 4.5 μm, obtained using the Spitzer Space Telescope. For WASP-19b, we measure secondary eclipse depths of 0.485%±0.024% and 0.584%±0.029% at 3.6 and 4.5 μm, which are consistent with a single blackbody with effective temperature 2372 ± 60 K. The measured 3.6 and 4.5 μm secondary eclipse depths for HAT-P-7b are 0.156%±0.009% and 0.190%±0.006%, which are well described by a single blackbody with effective temperature 2667 ± 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, which suggests 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 μm nightside planetary brightness for HAT-P-7b may be indicative of an enhanced global C/O ratio. We compute Bond albedos of 0.38 ± 0.06 and 0 (<0.08 at 1σ) 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.
- OSTI ID:
- 22869035
- Journal Information:
- Astrophysical Journal, Vol. 823, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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