Extremely Long Convergence Times in a 3D GCM Simulation of the Sub-Neptune Gliese 1214b

Wang, Huize; Wordsworth, R.

doi:10.3847/1538-4357/ab6dcc

Cited by 44 publications

(51 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This situation may be the case for WASP-43b but also generally for ultra-hot Jupiters (see Table 1, most tidally locked ultra-hot Jupiter are expected to have rotation periods faster than 1.5 days). The possible importance to resolve deeper layers and a sufficiently long simulation times has been further confirmed by Wang & Wordsworth (2020); Showman et al (2020). Here, we take the opportunity to offer a first discussion on what effect the choice of the inner boundary may have on the cloud coverage of the hot giant gas planets, WASP-43b.…”

Section: The Effect Of the Inner Boundary On Gcm Results For The Example Of Wasp-43bmentioning

confidence: 81%

Cloud property trends in hot and ultra-hot giant gas planets (WASP-43b, WASP-103b, WASP-121b, HAT-P-7b, and WASP-18b)

Helling

Lewis

Samra

et al. 2021

A&A

View full text Add to dashboard Cite

Context. Ultra-hot Jupiters are the hottest exoplanets that have been discovered so far. Observations begin to provide insight into the composition of their extended atmospheres and their chemical day/night asymmetries. Both are strongly affected by cloud formation. Aims. We explore trends in cloud properties for a sample of five giant gas planets: the hot gas giant WASP-43b and the four ultra-hot Jupiters (UHJs) WASP-18b, HAT-P-7b, WASP-103b, and WASP-121b. This provides a reference frame for cloud properties for the JWST targets WASP-43b and WASP-121b. We further explore chemically inert tracers to observe geometrical asymmetries of UHJs and if the location of the inner boundary of a 3D global circulation model (3D GCM) matters for the clouds that form. Methods. A homogeneous set of 3D GCM results was used as input for a kinetic cloud formation code to evaluate the cloud opacity and gas parameters such as C/O, mean molecular weight, and degree of ionisation. We cast our results in terms of integrated quantities to enable a global comparison between the sample planets. Results. The large day/night temperature differences of UHJs cause the following chemical asymmetries: cloud-free days but cloudy nights, atomic versus molecular gases and their different mean molecular weights, deep thermal ionospheres versus low-ionised atmospheres, and undepleted versus enhanced C/O. WASP-18b, as the heaviest planet in the sample, has the lowest global C/O. Conclusions. The global climate may be considered as similar amongst UHJs, but different to that of hot gas giants. The local weather, however, is individual for each planet since the local thermodynamic conditions, and hence the local cloud and gas properties, differ. The morning and the evening terminator of UHJs will carry signatures of their strong chemical asymmetry such that ingress and egress asymmetries can be expected. An increased C/O ratio is a clear sign of cloud formation, making cloud modelling a necessity when utilising C/O (or other mineral ratios) as a tracer for planet formation. The changing geometrical extension of the atmosphere from the day to the nightside may be probed through chemically inert species such as helium. Ultra-hot Jupiters are likely to develop deep atmospheric ionospheres which may impact the atmosphere dynamics through magneto-hydrodynamic processes.

show abstract

Section: The Effect Of the Inner Boundary On Gcm Results For The Example Of Wasp-43bmentioning

confidence: 81%

Cloud property trends in hot and ultra-hot giant gas planets (WASP-43b, WASP-103b, WASP-121b, HAT-P-7b, and WASP-18b)

Helling

Lewis

Samra

et al. 2021

A&A

View full text Add to dashboard Cite

show abstract

“…Following the recommendation of Sainsbury-Martinez et al (2019), we initialized our model with a hot adiabatic temperature profile. This allows for a comparatively fast convergence of the model to a steady state, even for the deep atmospheric layers, which are known to exhibit prohibitively long convergence times (additionally, see the discussions in Mayne et al 2017;Carone et al 2020;Wang & Wordsworth 2020). From there, all models were run for 1500 (Earth) days with time steps of 25 seconds, and the output has been averaged over the final 100 days of the simulation.…”

Section: Dynamical Climatementioning

confidence: 99%

“…Indeed, it has been shown that atmospheric chemistry can be altered by the internal temperature (Agúndez et al 2014b;Fortney et al 2020). On top of that, the convergence of deep atmospheric layers is a well-known problem in GCM simulations (Amundsen et al 2016;Mayne et al 2017;Carone et al 2020;Wang & Wordsworth 2020;Showman et al 2020). As input temperatures for chemical disequilibrium studies are often derived from GCM simulations (e.g.…”

Section: Observing Methanementioning

confidence: 99%

“…The assumed temperature profile in the deep part of the atmosphere is crucial to the chemistry, not only locally, but throughout the vertical extent of the atmosphere if quenched. However, unlike the 3D temperature structure at lower pressures, which can be relatively well constrained with a GCM, the deep thermal structure is often ill-constrained by GCMs, because it evolves very slowly (Carone et al 2020;Mendonça 2020;Wang & Wordsworth 2020;Showman et al 2020). This can result in temperature-profiles that are only partially converged, featuring a small thermal inversion in the deep ( ≈ 10 bar) layers (e.g.…”

Section: Temperatures In the Deep Atmospherementioning

confidence: 99%

See 1 more Smart Citation

Grid of pseudo-2D chemistry models for tidally locked exoplanets – I. The role of vertical and horizontal mixing

Baeyens

Decin

Carone

et al. 2021

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The atmospheres of synchronously rotating exoplanets are intrinsically three-dimensional, and fast vertical and horizontal winds are expected to mix the atmosphere, driving the chemical composition out of equilibrium. Due to the longer computation times associated with multi-dimensional forward models, horizontal mixing has only been investigated for a few case studies. In this paper, we aim to generalize the impact of horizontal and vertical mixing on the chemistry of exoplanet atmospheres over a large parameter space. We do this by applying a sequence of post-processed forward models for a large grid of synchronously rotating gaseous exoplanets, where we vary the effective temperature (between 400 K and 2600 K), surface gravity, and rotation rate. We find that there is a dichotomy in the horizontal homogeneity of the chemical abundances. Planets with effective temperatures below 1400 K tend to have horizontally homogeneous, vertically quenched chemical compositions, while planets hotter than 1400 K exhibit large compositional day-night differences for molecules such as CH4. Furthermore, we find that the planet’s rotation rate impacts the planetary climate, and thus also the molecular abundances and transmission spectrum. By employing a hierarchical modelling approach, we assess the relative importance of disequilibrium chemistry on the exoplanet transmission spectrum, and conclude that the temperature has the most profound impact. Temperature differences are also the main cause of limb asymmetries, which we estimate could be observable with the James Webb Space Telescope. This work highlights the value of applying a consistent modelling setup to a broad parameter space in exploratory theoretical research.

show abstract

“…Convergence of the whole simulated domain is therefore bottlenecked by the extremely long radiative timescale in the deep layers. Recent GCM experiments by Wang and Wordsworth (2020) showed that several hundred simulated years are needed for the deep flow to converge if assuming an 80-bar bottom boundary pressure. Mendonça (2020) showed that several tens of simulated years are required for the equatorial jet to equilibrate.…”

Section: Deep Boundary Conditions and Integration Timesmentioning

confidence: 99%

Atmospheric Dynamics of Hot Giant Planets and Brown Dwarfs

2020

View full text Add to dashboard Cite

Groundbased and spacecraft telescopic observations, combined with an intensive modeling effort, have greatly enhanced our understanding of hot giant planets and brown dwarfs over the past ten years. Although these objects are all fluid, hydrogen worlds with stratified atmospheres overlying convective interiors, they exhibit an impressive diversity of atmospheric behavior. Hot Jupiters are strongly irradiated, and a wealth of observations constrain the day-night temperature differences, circulation, and cloudiness. The intense stellar irradiation, presumed tidal locking and modest rotation leads to a novel regime of strong day-night radiative forcing. Circulation models predict large day-night temperature differences, global-scale eddies, patchy clouds, and, in most cases, a fast eastward jet at the equator—equatorial superrotation. The warm Jupiters lie farther from their stars and are not generally tidally locked, so they may exhibit a wide range of rotation rates, obliquities, and orbital eccentricities, which, along with the weaker irradiation, leads to circulation patterns and observable signatures predicted to differ substantially from hot Jupiters. Brown dwarfs are typically isolated, rapidly rotating worlds; they radiate enormous energy fluxes into space and convect vigorously in their interiors. Their atmospheres exhibit patchiness in clouds and temperature on regional to global scales—the result of modulation by large-scale atmospheric circulation. Despite the lack of irradiation, such circulations can be driven by interaction of the interior convection with the overlying atmosphere, as well as self-organization of patchiness due to cloud-dynamical-radiative feedbacks. Finally, irradiated brown dwarfs help to bridge the gap between these classes of objects, experiencing intense external irradiation as well as vigorous interior convection. Collectively, these diverse objects span over six orders of magnitude in intrinsic heat flux and incident stellar flux, and two orders of magnitude in rotation rate—thereby placing strong constraints on how the circulation of giant planets (broadly defined) depend on these parameters. A hierarchy of modeling approaches have yielded major new insights into the dynamics governing these phenomena.

show abstract

Extremely Long Convergence Times in a 3D GCM Simulation of the Sub-Neptune Gliese 1214b

Cited by 44 publications

References 62 publications

Cloud property trends in hot and ultra-hot giant gas planets (WASP-43b, WASP-103b, WASP-121b, HAT-P-7b, and WASP-18b)

Cloud property trends in hot and ultra-hot giant gas planets (WASP-43b, WASP-103b, WASP-121b, HAT-P-7b, and WASP-18b)

Grid of pseudo-2D chemistry models for tidally locked exoplanets – I. The role of vertical and horizontal mixing

Atmospheric Dynamics of Hot Giant Planets and Brown Dwarfs

Contact Info

Product

Resources

About