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  1. Book ; Online: Evidence of Radius Inflation in Radiative GCM Models of WASP-76b due to the Advection of Potential Temperature

    Sainsbury-Martinez, Felix / Tremblin, Pascal / Schneider, Aaron David / Carone, Ludmila / Baraffe, Isabelle / Chabrier, Gilles / Helling, Christiane / Decin, Leen / Jørgensen, Uffe Gråe

    2023  

    Abstract: Understanding the discrepancy between the radii of observed hot Jupiters and standard 'radiative-convective' models remains a hotly debated topic in the exoplanet community. One mechanism which has been proposed to bridge this gap, and which has recently ...

    Abstract Understanding the discrepancy between the radii of observed hot Jupiters and standard 'radiative-convective' models remains a hotly debated topic in the exoplanet community. One mechanism which has been proposed to bridge this gap, and which has recently come under scrutiny, is the vertical advection of potential temperature from the irradiated outer atmosphere deep into the interior, heating the deep, unirradiated, atmosphere, warming the internal adiabat, and resulting in radius inflation. Specifically, a recent study which explored the atmosphere of WASP-76b using a 3D, non-grey, GCM suggested that their models lacked radius inflation, and hence any vertical enthalpy advection. Here we perform additional analysis of these, and related, models, focusing on an explicit analysis of vertical enthalpy transport and the resulting heating of the deep atmosphere compared with 1D models. Our results indicate that, after any evolution linked with initialisation, all the WASP-76b models considered here exhibit significant vertical enthalpy transport, heating the deep atmosphere significantly when compared with standard 1D models. Furthermore, comparison of a long time-scale (and hence near steady-state) model with a Jupiter-like internal-structure model suggests not only strong radius-inflation, but also that the model radius, $1.98 \mathrm{R_{J}}$, may be comparable with observations ($1.83\pm0.06 \mathrm{R_{J}}$). We thus conclude that the vertical advection of potential temperature alone is enough to explain the radius inflation of WASP-76b, and potentially other irradiated gas giants, albeit with the proviso that the exact strength of the vertical advection remains sensitive to model parameters, such as the inclusion of deep atmospheric drag.

    Comment: Accepted for publication in MNRAS
    Keywords Astrophysics - Earth and Planetary Astrophysics
    Subject code 551
    Publishing date 2023-06-21
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Book ; Online: Harnessing machine learning for accurate treatment of overlapping opacity species in general circulation models

    Schneider, Aaron David / Mollière, Paul / Louppe, Gilles / Carone, Ludmila / Jørgensen, Uffe Gråe / Decin, Leen / Helling, Christiane

    2023  

    Abstract: To understand high precision observations of exoplanets and brown dwarfs, we need detailed and complex general circulation models (GCMs) that incorporate hydrodynamics, chemistry, and radiation. For this study, we specifically examined the coupling ... ...

    Abstract To understand high precision observations of exoplanets and brown dwarfs, we need detailed and complex general circulation models (GCMs) that incorporate hydrodynamics, chemistry, and radiation. For this study, we specifically examined the coupling between chemistry and radiation in GCMs and compared different methods for the mixing of opacities of different chemical species in the correlated-k assumption, when equilibrium chemistry cannot be assumed. We propose a fast machine learning method based on DeepSets (DS), which effectively combines individual correlated-k opacities (k-tables). We evaluated the DS method alongside other published methods such as adaptive equivalent extinction (AEE) and random overlap with rebinning and resorting (RORR). We integrated these mixing methods into our GCM (expeRT/MITgcm) and assessed their accuracy and performance for the example of the hot Jupiter HD~209458 b. Our findings indicate that the DS method is both accurate and efficient for GCM usage, whereas RORR is too slow. Additionally, we observed that the accuracy of AEE depends on its specific implementation and may introduce numerical issues in achieving radiative transfer solution convergence. We then applied the DS mixing method in a simplified chemical disequilibrium situation, where we modeled the rainout of TiO and VO, and confirmed that the rainout of TiO and VO would hinder the formation of a stratosphere. To further expedite the development of consistent disequilibrium chemistry calculations in GCMs, we provide documentation and code for coupling the DS mixing method with correlated-k radiative transfer solvers. The DS method has been extensively tested to be accurate enough for GCMs; however, other methods might be needed for accelerating atmospheric retrievals.

    Comment: Accepted for publication in A&A, language edited version
    Keywords Astrophysics - Earth and Planetary Astrophysics ; Computer Science - Machine Learning
    Subject code 518
    Publishing date 2023-11-01
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Book ; Online: Exploring the deep atmospheres of HD 209458b and WASP-43b using a non-gray general circulation model

    Schneider, Aaron David / Carone, Ludmila / Decin, Leen / Jørgensen, Uffe Gråe / Mollière, Paul / Baeyens, Robin / Kiefer, Sven / Helling, Christiane

    2022  

    Abstract: Simulations with a 3D general circulation model (GCM) suggest that one potential driver behind the observed radius inflation in hot Jupiters may be the downward advection of energy from the highly irradiated photosphere into the deeper layers. Here, we ... ...

    Abstract Simulations with a 3D general circulation model (GCM) suggest that one potential driver behind the observed radius inflation in hot Jupiters may be the downward advection of energy from the highly irradiated photosphere into the deeper layers. Here, we compare dynamical heat transport within the non-inflated hot Jupiter WASP-43b and the canonical inflated hot Jupiter HD 209458b, with similar effective temperatures. We investigate to what extent the radiatively driven heating and cooling in the photosphere (at pressures smaller than 1 bar) influence the deeper temperature profile (at pressures between 1 to 700 bar). Our simulations with the new non-gray 3D radiation-hydrodynamical model expeRT/MITgcm show that the deep temperature profile of WASP-43b is associated with a relatively cold adiabat. The deep layers of HD 209458b, however, do not converge and remain nearly unchanged regardless of whether a cold or a hot initial state is used. Furthermore, we show that different flow structures in the deep atmospheric layers arise. There, we find that WASP-43b exhibits a deep equatorial jet, driven by the relatively fast tidally locked rotation of this planet (0.81 days), as compared to HD 209458b (3.47 days). However, by comparing simulations with different rotation periods, we find that the resulting flow structures only marginally influence the temperature evolution in the deep atmosphere, which is almost completely dominated by radiative heating and cooling. Furthermore, we find that the evolution of deeper layers can influence the 3D temperature structure in the photosphere of WASP-43b. Thus, dayside emission spectra of WASP-43b may shed more light onto the dynamical processes occurring at greater depths.

    Comment: previously accepted for publication in A&A, needed bug fixing, paper updated and back at A&A
    Keywords Astrophysics - Earth and Planetary Astrophysics
    Subject code 551
    Publishing date 2022-02-18
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Book ; Online: Ejecta Evolution Following a Planned Impact into an Asteroid

    Kareta, Theodore / Thomas, Cristina / Li, Jian-Yang / Knight, Matthew M. / Moskovitz, Nicholas / Rozek, Agata / Bannister, Michele T. / Ieva, Simone / Snodgrass, Colin / Pravec, Petr / Ryan, Eileen V. / Ryan, William H. / Fahnestock, Eugene G. / Rivkin, Andrew S. / Chabot, Nancy / Fitzsimmons, Alan / Osip, David / Lister, Tim / Sarid, Gal /
    Hirabayashi, Masatoshi / Farnham, Tony / Tancredi, Gonzalo / Michel, Patrick / Wainscoat, Richard / Weryk, Rob / Burrati, Bonnie / Pittichova, Jana / Ridden-Harper, Ryan / Tan, Nicole J. / Tristram, Paul / Brown, Tyler / Bonavita, Mariangela / Burgdorf, Martin / Khalouei, Elahe / Longa, Penelope / Rabus, Markus / Sajadian, Sedighe / Jorgensen, Uffe Graae / Dominik, Martin / Kikwaya, Jean-Baptiste / Epifani, Elena Mazzotta / Dotto, Elisabetta / Deshapriya, J. D. Prasanna / Hasselmann, Pedro H. / Dall'Ora, Massimo / Abe, Lyu / Guillot, Tristan / Mekarnia, Djamel / Agabi, Abdelkrim / Bendjoya, Philippe / Suarez, Olga / Triaud, Amaury / Gasparetto, Thomas / Gunther, Maximillian N. / Kueppers, Michael / Merin, Bruno / Chatelain, Joseph / Gomez, Edward / Usher, Helen / Stoddard-Jones, Cai / Bartnik, Matthew / Bellaver, Michael / Chetan, Brenna / Dugan, Emma / Fallon, Tori / Fedewa, Jeremy / Gerhard, Caitlyn / Jacobson, Seth A. / Painter, Shane / Peterson, David-Michael / Rodriguez, Joseph E. / Smith, Cody / Sokolovsky, Kirill V. / Sullivan, Hannah / Townley, Kate / Watson, Sarah / Webb, Levi / Trigo-Rodrıguez, Josep M. / Llenas, Josep M. / Perez-Garcıa, Ignacio / Castro-Tirado, A. J. / Vincent, Jean-Baptiste / Migliorini, Alessandra / Lazzarin, Monica / La Forgia, Fiorangela / Ferrari, Fabio / Polakis, Tom / Skiff, Brian

    The First Five Weeks

    2023  

    Abstract: The impact of the DART spacecraft into Dimorphos, moon of the asteroid Didymos, changed Dimorphos' orbit substantially, largely from the ejection of material. We present results from twelve Earth-based facilities involved in a world-wide campaign to ... ...

    Abstract The impact of the DART spacecraft into Dimorphos, moon of the asteroid Didymos, changed Dimorphos' orbit substantially, largely from the ejection of material. We present results from twelve Earth-based facilities involved in a world-wide campaign to monitor the brightness and morphology of the ejecta in the first 35 days after impact. After an initial brightening of ~1.4 magnitudes, we find consistent dimming rates of 0.11-0.12 magnitudes/day in the first week, and 0.08-0.09 magnitudes/day over the entire study period. The system returned to its pre-impact brightness 24.3-25.3 days after impact through the primary ejecta tail remained. The dimming paused briefly eight days after impact, near in time to the appearance of the second tail. This was likely due to a secondary release of material after re-impact of a boulder released in the initial impact, through movement of the primary ejecta through the aperture likely played a role.

    Comment: 16 pages, 5 Figures, accepted in the Astrophysical Journal Letters (ApJL) on October 16, 2023
    Keywords Astrophysics - Earth and Planetary Astrophysics
    Subject code 306
    Publishing date 2023-10-18
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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