The Influence of Atmospheric Dynamics on the Infrared Spectra and Light Curves of Hot Jupiters

By Jon Fortney, Curtis S. Cooper, A. Showman, M. Marley, R. Freedman. 2006

148 citations recorded by the source corpus.

We explore the infrared spectrum of a three-dimensional dynamical model of planet HD 209458b as a function of orbital phase. The dynamical model predicts dayside atmospheric pressure-temperature profiles that are much more isothermal at pressures less than 1 bar than one-dimensional radiative-convective models have found. The resulting dayside thermal spectra are very similar to a blackbody, and only weak water absorption features are seen at short wavelengths. The dayside emission is consequently in better agreement with ground-based and space-based secondary eclipse data than any previous models, which predict strong flux peaks and deep absorption features. At other orbital phases, absorption due to carbon monoxide and methane is also predicted. We compute the spectra under two treatments of atmospheric chemistry: one uses the predictions of equilibrium chemistry, and the other uses nonequilibrium chemistry, which ties the timescales of methane and carbon monoxide chemistry to dynamical timescales. As a function of orbital phase, we predict planet-to-star flux ratios for standard infrared bands and all Spitzer Space Telescope bands. In Spitzer bands, we predict two- to fifteenfold variation in planetary flux as a function of orbital phase with equilibrium chemistry, and two- to fourfold variation with nonequilibrium chemistry. Variation is generally more pronounced in bands from 3 to 10 μm than at longer wavelengths. The orbital phase of maximum thermal emission in infrared bands is 15-45 orbital degrees before the time of secondary eclipse. Changes in flux as a function of orbital phase for HD 209458b should be observable with Spitzer, given the previously achieved observational error bars.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/1d3d49b6d12dc6fab055d9710e6bded448601a9f

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In Astronomy and Astrophysics

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

In Instrumentation

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

Citations in the corpus

• A chemical model for the atmosphere of hot Jupiters (2012, background): “Deviations from the thermodynamic equilibrium have been discussed with timescale arguments (e.g. Lodders & Fegley 2002; Fortney et al. 2006, 2008b; Visscher et al. 2006, 2010; Madhusudhan & Seager 2010) or modeled with a few reactions describing the CO-CH4 conversion coupled with the dynamics…”
• CAN TiO EXPLAIN THERMAL INVERSIONS IN THE UPPER ATMOSPHERES OF IRRADIATED GIANT PLANETS? (2009, background): “Radiative equilibrium radiative transfer models of close-in EGP atmospheres (Sudarsky et al. 2003; Hubeny et al. 2003; Burrows et al. 2007a; Fortney et al. 2006, 2008) predict that, in at least some of the planets inferred to have inversions (e.g., HD 209458b), there is a cooler region below the…”
• TRANSMISSION SPECTRA OF THREE-DIMENSIONAL HOT JUPITER MODEL ATMOSPHERES (2009, methodology): “Its planet-wide meanP-T profile is close to the boundary where CO and CH4 have equal abundances (Fortney et al. 2006b), given chemical equilibrium.”
• 3.6 AND 4.5 μm PHASE CURVES AND EVIDENCE FOR NON-EQUILIBRIUM CHEMISTRY IN THE ATMOSPHERE OF EXTRASOLAR PLANET HD 189733b (2012, methodology): “We calculate phase curves in the 3.6, 4.5, 8.0, and 24 µm Spitzer bands for each model following the method described in Fortney et al. (2006).”
• A DETECTION OF WATER IN THE TRANSMISSION SPECTRUM OF THE HOT JUPITER WASP-12b AND IMPLICATIONS FOR ITS ATMOSPHERIC COMPOSITION (2015, background): “The amplitude of these features has often been smaller than predicted for transiting planets, due to the presence of clouds or haze and shallower thermal profiles (e.g. Fortney et al. 2006; Char- bonneau et al. 2002; Deming et al. 2013).”
• MULTIWAVELENGTH CONSTRAINTS ON THE DAY–NIGHT CIRCULATION PATTERNS OF HD 189733b (2008, methodology): “…on the atmospheric dynamics of these planets will be applicable to smaller, core-dominated planets such as HD 149026b and GJ 436b (Butler et al. 2004; Sato et al. 2005; Fortney et al. 2006a; Gillon et al. 2007; Deming et al. 2007; Torres et al. 2007; Adams et al. 2008; Winn et al. 2008).”
• From thermal dissociation to condensation in the atmospheres of ultra hot Jupiters: WASP-121b in context (2018, methodology): “This method, similar to the calculation of Fortney et al. (2006) and Parmentier et al. (2016), naturally takes into account geometrical effects such as limb darkening.”
• A Spitzer Spectrum of the Exoplanet HD 189733b (2007, background): “Owing to an orbital radius of 0.031 AU, the upper atmospheric temperature of the planet 1Alfred P. Sloan Research Fellow is ≥ 1000 K (Fortney et al. 2006a).”
• A CORRELATION BETWEEN STELLAR ACTIVITY AND HOT JUPITER EMISSION SPECTRA (2010, background): “…know the nature of the absorber required to create these inversions; it was initially suggested that gas-phase TiO might provide the necessary opacity(Hubeny et al. 2003; Burrows et al. 2007, 2008; Fortney et al. 2006, 2008), but this theory cannot explain the full range of current observations.”
• Hot nights on extrasolar planets: mid‐infrared phase variations of hot Jupiters (2007, methodology): “In light of the models of Fortney et al. (2006), we assume that the planet’s day and night-side radiate as blackbodies F = Bλ(T) and that the host star emits with a mid-IR brightness temperature Tbright (we use Tbright = 0.87Teff at 8 µm based on the models of Kurucz 1979).”
• Atmospheric Circulation of Hot Jupiters: Three-dimensional Circulation Models of HD 209458b and HD 189733b with Simplified Forcing (2008, unknown): “One-dimensional atmosphere models suggest that gasous TiO and VO are cold trapped at pressures of ∼ 10 - 100bars where solid clouds incorporating Ti and V form, which suggests that TiO and VO should be absent in the observable atmosphere (e.g., Hubeny et al. 2003; Fortney et al. 2006b).”
• DISEQUILIBRIUM CARBON, OXYGEN, AND NITROGEN CHEMISTRY IN THE ATMOSPHERES OF HD 189733b AND HD 209458b (2011, methodology): “D “4pi” profile from Fortney et al. (2006a, 2010) is the coolest of all our models at 10-30 bars, resulting in the largest quenched HCN mole fraction in this model.”
• TRANSITIONS IN THE CLOUD COMPOSITION OF HOT JUPITERS (2016, methodology): “This method, similar to the calculation of Fortney et al. (2006) naturally takes into account geometrical effects such as limb darkening.”
• SPITZER PHASE CURVE CONSTRAINTS FOR WASP-43b AT 3.6 AND 4.5 μm (2016, methodology): “We calculate disk-integrated GCM phase curves following the procedures defined by Showman et al. (2008) and Fortney et al. (2006) then, in Figure 12, compare them to our measured phase curves from both 3.6 µm visits and the 4.5 µm visit.”
• A Unified Theory for the Atmospheres of the Hot and Very Hot Jupiters: Two Classes of Irradiated Atmospheres (2007, methodology): “At that point, looking at the work of Fortney et al. (2006b) and especially Hubeny et al. (2003), Harrington et al. (2007) could have postulated that all objects more irradiate than HD 149026b may possess inversions due to TiO/VO opacity, but given the single-band detection of HD 149026b, caution…”
• THE STATISTICS OF ALBEDO AND HEAT RECIRCULATION ON HOT EXOPLANETS (2009, background): “The presence or lack of a stratospheric temperature inversion (Hubeny et al. 2003; Fortney et al. 2006; Burrows et al. 2007, 2008; Zahnle et al. 2009) on the day-sides of exoplanets has been invoked to explain a purported bi-modality in recirculation efficiency on hot Jupiters (Fortney et al. 2008).”
• The 3.6-8.0 μm Broadband Emission Spectrum of HD 209458b: Evidence for an Atmospheric Temperature Inversion (2007, background): “However, Fortney et al. (2006a) suggested that this planet might have a close-to-isothermal temperature profile on the dayside, which would wash out any absorption bands.”