Emergent Spectral Fluxes of Hot Jupiters: An Abrupt Rise in Dayside Brightness Temperature Under Strong Irradiation

Deming, Drake; Line, Michael R.; Knutson, Heather A.; Crossfield, Ian J. M.; Kempton, Eliza M.-R.; Komacek, Thaddeus D.; Wallack, Nicole L.; Fu, Guangwei

doi:10.3847/1538-3881/acb210

“…We suggest a high-resolution spectroscopic search for the molecule and additional JWST observations to constrain the T-P profile. We note that the equilibrium temperature of HD 149026b is 1694 K, which is very close to the 1730 K equilibrium temperature around which an abrupt rise in dayside brightness temperature has been recently found by Deming et al (2023).…”

Section: Nightsidesupporting

confidence: 84%

The Atmosphere of HD 149026b: Low Metal Enrichment and Weak Energy Transport

Gagnebin,

Mukherjee,

Fortney

et al. 2024

ApJ

2

0

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Recent JWST eclipse spectra of the high-density hot Saturn HD 149026b between 2.35 and 5.08 μm have allowed for in-depth study of its atmosphere. To understand its atmospheric properties, we have created a grid of 1D radiative-convective–thermochemical–equilibrium atmosphere models and spectra with PICASO 3.0. In agreement with previous work, we find that the presence of gaseous TiO creates a thermal inversion, which is inconsistent with the data. The presence of gaseous VO, however, which condenses at temperatures 200 K cooler, does not cause such inversions but alters the temperature–pressure profile of the atmosphere. We estimate an atmospheric metallicity of 14 − 8 + 12 × solar without VO and 20 − 8 + 11 × solar with VO, a factor of ∼10 times smaller than previous work from Bean et al., who relied on atmosphere retrievals. We attribute this significant difference in metallicity to a larger temperature gradient at low pressures in radiative equilibrium models. Such models with lower metallicities readily fit the strong CO2 feature at 4.3 μm. Our lower estimated metallicity makes HD 149026b more consistent with the mass–metallicity relationship for other giant planets. We find a C/O ratio of 0.67 − 0.27 + 0.06 with and without VO. The best-fit heat redistribution factor without VO is 1.17, a very high value suggesting very little dayside energy transport and no energy transport to the nightside. The heat redistribution factor shrinks to a more plausible value of 0.91 − 0.05 + 0.05 , with VO, which we regard as circumstantial evidence for the molecule in the atmosphere of HD 149026b.

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“…The brightness temperatures measured from Spitzer secondary eclipse observations are shown from ref. 123 . The corresponding pressures and ranges are derived from the best-fit model contribution function, with the y-axis range encapsulating 80% of the total emitted flux.…”

Section: Extended Data Figures and Tablesmentioning

confidence: 99%

A warm Neptune’s methane reveals core mass and vigorous atmospheric mixing

Sing,

Rustamkulov,

Thorngren

et al. 2024

Nature

10

0

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Observations of transiting gas giant exoplanets have revealed a pervasive depletion of methane 1 – 4 , which has only recently been identified atmospherically 5 , 6 . The depletion is thought to be maintained by disequilibrium processes such as photochemistry or mixing from a hotter interior 7 – 9 . However, the interiors are largely unconstrained along with the vertical mixing strength and only upper limits on the CH 4 depletion have been available. The warm Neptune WASP-107b stands out among exoplanets with an unusually low density, reported low core mass 10 , and temperatures amenable to CH 4 , though previous observations have yet to find the molecule 2 , 4 . Here we present a JWST-NIRSpec transmission spectrum of WASP-107b that shows features from both SO 2 and CH 4 along with H 2 O, CO 2 , and CO. We detect methane with 4.2 σ significance at an abundance of 1.0 ± 0.5 ppm, which is depleted by 3 orders of magnitude relative to equilibrium expectations. Our results are highly constraining for the atmosphere and interior, which indicate the envelope has a super-solar metallicity of 43 ± 8 × solar, a hot interior with an intrinsic temperature of T int = 460 ± 40 K, and vigorous vertical mixing which depletes CH 4 with a diffusion coefficient of K zz = 10 11.6±0.1 cm 2 s −1 . Photochemistry has a negligible effect on the CH 4 abundance but is needed to account for the SO 2 . We infer a core mass of , which is much higher than previous upper limits 10 , releasing a tension with core-accretion models 11 .

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“…I take the derived dayside brightness temperatures from Deming et al (2023) and average the 3.6 micron and 4.5 micron temperatures to arrive at an approximate estimate of the planetary dayside temperature to use in calculating the albedo. Thus, the thermally corrected albedos of CoRoT-1 b can be calculated.…”

Section: A Wavelength-dependent Albedo Of Corot-1 B?mentioning

confidence: 99%

A Robust Four-Phase Equilibrium Calculation Algorithm for Hydrocarbon-Water Mixtures at Pressure and Enthalpy Specifications

Li

¹

,

Li

²

2023

SPE Western Regional Meeting

1

0

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A robust multiphase equilibrium calculation algorithm with pressure and enthalpy (PH) specifications, i.e., an isenthalpic algorithm, plays an important role in the compositional simulations of steam-based enhanced oil recovery (EOR) applications (such as steam and solvent co-injection process for heavy oil recovery). Up to now, there are few works documented in the literature focusing on four-phase isenthalpic algorithms. In this paper, we propose a four-phase isenthalpic algorithm with a nested approach. It contains an inner loop and an outer loop. In the inner loop, a well-designed isobaric/isothermal (PT) multiphase (up to four phases) equilibrium algorithm is employed to solve the phase fractions and compositions, while the Brent's method (1971) is applied in the outer loop to update the temperature by satisfying the energy conservation equation. We test the performance of the proposed algorithm using four case studies under different pressure-enthalpy conditions. Calculation results demonstrate that the proposed PH algorithm is always able to converge to the correct phase equilibria with only tens of PT algorithm calls.

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Emergent Spectral Fluxes of Hot Jupiters: An Abrupt Rise in Dayside Brightness Temperature Under Strong Irradiation

Cited by 11 publications

References 124 publications

The Atmosphere of HD 149026b: Low Metal Enrichment and Weak Energy Transport

The Atmosphere of HD 149026b: Low Metal Enrichment and Weak Energy Transport

A warm Neptune’s methane reveals core mass and vigorous atmospheric mixing

A Robust Four-Phase Equilibrium Calculation Algorithm for Hydrocarbon-Water Mixtures at Pressure and Enthalpy Specifications

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