A. P. Showman

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'Hot Jupiter' extrasolar planets are expected to be tidally locked because they are close (<0.05 astronomical units, where 1 au is the average Sun-Earth distance) to their parent stars, resulting in permanent daysides and nightsides. By observing systems where the planet and star periodically eclipse each other, several groups have been able to estimate the(More)
Large-scale nonlinear simulations of Jupiter's 5-micron hot spots produce long-lived coherent structures that cause subsidence in local regions, explaining the low cloudiness and the dryness measured by the Galileo probe inside a hot spot. Like observed hot spots, the simulated coherent structures are equatorially confined, have periodic spacing, propagate(More)
the fact that contraction produced by melting ice I offsets expansion produced by melting high-pressure ice phases. Solid– We explore the hypothesis that passage through an eccentricsolid phase transitions cause negligible satellite expansion. Lithity-pumping resonance could lead to the resurfacing of Ganyospheric stresses caused by expansion of 2% over 10(More)
We present global, three-dimensional numerical simulations of HD 189733b and HD 209458b that couple the atmospheric dynamics to a realistic representation of non-gray cloud-free radiative transfer. The model, which we call the Substellar and Planetary Atmospheric Radiation and Circulation (SPARC) model, adopts the MITgcm for the dynamics and uses the(More)
Jupiter has half a dozen eastward jet streams in each hemisphere. On average, Earth has only one in each hemisphere. Jupiter has weather patterns (“storms”) that last for centuries. Earth has stationary weather patterns fixed to the topography, but the average lifetime of a traveling storm is ∼1 week. Jupiter has no topography, i.e., no continents or(More)
column stretching, so that the NH3 , NH4SH, and water lifting condensation levels were pushed to 8, 16, and .20 bars, respecThe Galileo probe found the jovian abundance of H2S to be tively. In either case, the simplest form of this model requires 30% solar at the 8 bar level, while the abundance of water was the downdraft to be less dense than the(More)
Chemical equilibrium considerations suggest that, assuming solar elemental abundances, carbon on HD 209458b is sequestered primarily as carbon monoxide (CO) and methane (CH4). The relative mole fractions of CO(g) and CH4(g) in chemical equilibrium are expected to vary greatly according to variations in local temperature and pressure. We show, however, that(More)
Figure 1. Large flow imaged by the Titan Radar Mapper using the SAR mode during the Ta fly-by on October 26, 2004. The image covers an area about 150 km, centered at about 45 N, 30 W. The radar illumination is from the south. Note that the southern edges of the flow are brighter, consistent with the structure being raised above the relatively featureless(More)