Atmospheric Circulation of Hot Jupiters: Three-dimensional Circulation Models of HD 209458b and HD 189733b with Simplified Forcing

By A. Showman, Curtis S. Cooper, Jon Fortney, M. Marley. 2008

174 citations recorded by the source corpus.

We present global, three-dimensional numerical simulations of the atmospheric circulation on HD 209458b and HD 189733b and calculate the infrared spectra and light curves predicted by these simulations, which we compare with available observations. Radiative heating/cooling is parameterized with a simplified Newtonian relaxation scheme. Our simulations develop day-night temperature contrasts that vary strongly with pressure. At low pressure (<10 mbar), air flows from the substellar point toward the antistellar point, both along the equator and over the poles. At deeper levels, the flow develops an eastward equatorial jet with speeds of 3-4 km s−1, with weaker westward flows at high latitudes. This basic flow pattern is robust to variations in model resolution, gravity, radiative time constant, and initial temperature structure. Nightside spectra show deep absorption bands of H2O, CO, and/or CH4, whereas on the dayside these absorption bands flatten out or even flip into emission. This results from the strong effect of dynamics on the vertical temperature-pressure structure; the temperature decreases strongly with altitude on the nightside but becomes almost isothermal on the dayside. In Spitzer bandpasses, our predicted planet-to-star flux ratios vary by a factor of ~2-10 with orbital phase, depending on the wavelength and chemistry. For HD 189733b, where a detailed 8 μm light curve has been obtained, we correctly produce the observed phase offset of the flux maximum, but we do not explain the flux minimum and we overpredict the total flux variation. This discrepancy likely results from the simplifications inherent in the Newtonian relaxation scheme and provides motivation for incorporating realistic radiative transfer in future studies.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/7aec58ae48304ebc918fb0285c332a4d4beb3342

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In Astronomy and Astrophysics

1. N. Madhusudhan
2. Jon Fortney
3. A. Showman
4. M. Line
5. H. Knutson
6. D. Deming
7. V. Parmentier
8. M. Marley

Citations in the corpus

• INFRARED TRANSMISSION SPECTROSCOPY OF THE EXOPLANETS HD 209458b AND XO-1b USING THE WIDE FIELD CAMERA-3 ON THE HUBBLE SPACE TELESCOPE (2013, methodology): “Such an analysis could incorporate guidance from hydrodynamic models (Showman et al. 2008; Dobbs-Dixon et al. 2012; Showman et al. 2013; Rauscher & Menou 2013) to account for the longitudinal transfer of stellar irradiance, and could explore the full parameter space of composition and temperature…”
• TRANSMISSION SPECTRA OF THREE-DIMENSIONAL HOT JUPITER MODEL ATMOSPHERES (2009, methodology): “…dynamics using highly idealized prescriptions for the trmodynamic heating/cooling rate, such as a Newtonian relaxation scheme (Showman & Guillot 2002; Cooper & Showman 2005, 2006; Showman et al. 2008; Menou & Rauscher 2009; Rauscher & Menou 2009) or flux-limited diffusion (Dobbs-Dixon & Lin 2008).”
• WATER, METHANE, AND CARBON DIOXIDE PRESENT IN THE DAYSIDE SPECTRUM OF THE EXOPLANET HD 209458b (2009, background): “Models of atmospheric circulation for HD 209458b suggest that the zonal wind structure is a function of altitude (Showman et al. 2008), and mid-infrared dayside emission could vary (Rauscher et al. 2007, 2008; Showman et al. 2008).”
• INFERENCE OF INHOMOGENEOUS CLOUDS IN AN EXOPLANET ATMOSPHERE (2013, methodology): “…of general circulation models for tidally-locked hot-Jupiters forced using various methods, including Newtonian cooling (e.g. Cooper & Showman 2005; Showman et al. 2008; Dobbs-Dixon et al. 2010; Rauscher & Menou 2010; Heng et al. 2011a), dual-band radiative transfer (e.g. Heng et al. 2011b;…”
• 3D mixing in hot Jupiters atmospheres. I. Application to the day/night cold trap in HD 209458b (2013, background): “…models show that this day-night heating gradient can lead, at low pressures, to nightside temperatur s that are at least∼1000 K colder than dayside temperatures (.g., Showman et al. 2008, 2009; Dobbs-Dixon et al. 2010; Rauscher & Menou 2010, 2012a; Heng et al. 2011a,b; Perna et al. 2012).”
• DISEQUILIBRIUM CARBON, OXYGEN, AND NITROGEN CHEMISTRY IN THE ATMOSPHERES OF HD 189733b AND HD 209458b (2011, background): “…et al. 2007, 2009; Cooper & Showman 2006; Fortney et al. 2006a, 2008a, 2010; Richardson et al. 2007; Burrows et al. 2007, 2008; Cowan et al. 2007; Showman et al. 2008, 2009; Madhusudhan & Seager 2009, 2010a), and (4) the inferred presence of hazes, clouds, and Rayleigh scatterers that can…”
• INFLATING HOT JUPITERS WITH OHMIC DISSIPATION (2010, background): “In particular, the lower atmospheres (P & 0.1 Bars) of hot Jupiters are believed to be almost isothermal while the radiative/convective boundaries are thought to lie at P ∼ 100− 1000 Bars, depending on the planet (Showman et al. 2008).”
• ATMOSPHERIC HEAT REDISTRIBUTION ON HOT JUPITERS (2013, unknown): “…this timescale compar- ison could describe the pressure-, opacity-, and insolationdependence of the day-night temperature differences on hot Jupiters (Cooper & Showman 2005; Showman et al. 2008; Fortney et al. 2008; Rauscher & Menou 2010; Heng et al. 2011; Cowan & Agol 2011; Perna et al. 2012).”
• SPITZER PHASE CURVE CONSTRAINTS FOR WASP-43b AT 3.6 AND 4.5 μm (2016, methodology): “Murgas et al. (2014) also placed constraints on tidal decay rate of WASP-43b, finding a value ( ṗ = −0.15±0.06 s yr-1) that is consistent with that reported by Blecic et al. (2014).”
• EQUATORIAL SUPERROTATION ON TIDALLY LOCKED EXOPLANETS (2011, background): “…models of hot Jupiters exhibit relatively steady circulation patterns (Showman & Guillot 2002; Cooper & Showman 2005, 2006; Dobbs-Dixon & Lin 2008; Dobbs-Dixon et al. 2010; Showman et al. 2008, 2009; Rauscher & Menou 2010), and so we seek steady solutions in the presence of forcing and damping.”
• Transmission spectral properties of clouds for hot Jupiter exoplanets (2014, unknown): “1 of Showman et al. (2008) and Fig.”
• On the radiative equilibrium of irradiated planetary atmospheres (2010, methodology): “Opacities in the visible and infrared were adjusted to obtain a good match to the more detailed models of Fortney et al. (2008) and Showman et al. (2008) at vertical incidence.”
• CAN TiO EXPLAIN THERMAL INVERSIONS IN THE UPPER ATMOSPHERES OF IRRADIATED GIANT PLANETS? (2009, methodology): “According to the analysis of Showman et al. (2008a), on this planet τrad > τcirc at pressures deeper than 1 bar.”
• Exoplanetary Atmospheres: Key Insights, Challenges, and Prospects (2019, background): “At the same time, the first three-dimensional atmospheric circulation models were being developed for hot Jupiters (237) to explain the observed thermal phase curves.”
• ATMOSPHERIC CIRCULATION OF HOT JUPITERS: COUPLED RADIATIVE-DYNAMICAL GENERAL CIRCULATION MODEL SIMULATIONS OF HD 189733b and HD 209458b (2008, unknown): “In contrast, in our previous simulations forced by Newtonian heating/cooling (Showman et al. 2008a), the day-night temperature differences reached nearly 900K at 100 mbar and 1000K at 10 mbar.”
• MULTIWAVELENGTH CONSTRAINTS ON THE DAY–NIGHT CIRCULATION PATTERNS OF HD 189733b (2008, background): “These same models indicate that the daynight temperature difference should increase with altitude (Cooper & Showman 2005; Showman et al. 2008; Dobbs-Dixon & Lin 2008), but this change is modest over the factor of 2−3 variation in the pressures that are likely sensed by these two bandpasses.”