FORJADOS DE LA CASA DE INFORMACIÓN
FORJADO DE CUBIERTAS Cálculo de la deformación del forjado
326.01 — Exploring the Internal Structures of hot Jupiters using the GCM DYNAMICO: Deep, Hot, Adiabats as a Possible Solution to the Radius Infla- tion Problem
Felix Sainsbury-Martinez1; Pascal Wang2,1; Sebastian
Fromang3; Pascal Tremblin1; Thomas Dubos4; Yann
Meurdesoif5; Jermey Leconte6; Aymeric Spiga4; Is-
abelle Baraffe7; Nathan Mayne7; Florian Debras2; Gilles
Chabrier2,7; Ben Drummond7
1 MDLS, CEA Paris Saclay (Gif-sur-Yvette cedex, France) 2 ENS Lyon (Lyon, France)
3 DAP CEA Paris-Saclay (Saclay, France) 4 LMD/IPSL, Ecole Polytechnique (Saclay, France) 5 LSCE/IPSL, Universite Paris-Saclay (Saclay, France) 6 Universite de Bordeaux (Bordeaux, France)
7 Astrophysics, University of Exeter (Exeter, United Kingdom) The anomalously large radii of highly irradiated ex- oplanets have long remained a mystery to the Exo- planetary community, with many different solutions suggested and tested. These solutions have included tidal heating of the atmosphere, or ohmic heating from a strong magnetic field. Another solution was also suggested by Tremblin et Al. (2017): The in- flated radii of highly irradiated exoplanets can be ex- plained by the advection of potential temperature, via mass and longitudinal momentum conservation, leads to the deep atmosphere attaching to a hotter adiabat than would be suggested by 1D models, thus implying an inflated radius. In that paper this mech- anism was tested using 2D steady-state models, and successfully reproduced an inflated HD209458b sce- nario. Here we extend this work to both the time- dependent and 3D regimes using the GCM Dynam- ico (Itself developed as a new dynamical core for LMD-Z, and verified against Hot Jupiter benchmarks as part of this work), exploring the evolution of the deep P-T profile, and the stability of a deep adiabat as the steady state solution. As a result of these calcula- tions we confirm that a deep, hot, adiabat is both the target of long term evolution of the deep atmosphere, and is stable against typical forcing expected at deep
pressures — we also note that this deep adiabat takes a very significant time to form from an isothermal initial condition (hence why it has not previously been seen in GCM simulations beyond a kink in the deep profile), and suggest that future GCM models should use an adiabatic profile to initialise the deep atmosphere. Taken as a whole, our results confirm the theory of Tremblin et Al. (2017): the inflated radii of highly irradiated exoplanets can be explained by connecting the atmosphere with a deep, hot, internal adiabat.
326.02 — Admissible types of magnetospheres of hot Jupiters
Dmitry Bisikalo1
1 Institute of astronomy of the Russian Academy of Sciences (Moscow, Russian Federation)
The orbits of exoplanets of the hot Jupiters type, i.e., exoplanets with masses comparable to the mass of Jupiter and orbital semi-major axes less than 0.1 AU, as a rule, are located close to the Alfven point of the stellar wind of the parent star. At this, many hot Jupiters can be located in the sub-Alfven zone in which the magnetic pressure of the stellar wind exceeds its dynamic pressure. Therefore, magnetic field of the wind must play an extremely important role for the flow of the stellar wind around the atmo- spheres of the hot Jupiters. This factor must be con- sidered both in theoretical models and in the inter- pretation of observational data. The analysis shows that many typical hot Jupiters should have shock- less intrinsic magnetospheres, which, apparently, do not have counterparts in the Solar System. We con- firmed this inference by the three-dimensional nu- merical simulation of the flow of the parent star stel- lar wind around the hot Jupiter HD 209458b in which we took into account both proper magnetic field of the planet and magnetic field of the wind.
326.03 — Dynamical effects of hydrogen disso- ciation on atmospheric circulation of ultra-hot Jupiters
Xianyu Tan1; Thaddeus Komacek2
1 Department of Physics, University of Oxford (Oxford, England, United Kingdom)
2 University of Chicago (Chicago, Illinois, United States)
Recent secondary eclipse spectral and phase curve observations of ultra-hot Jupiters with dayside tem- peratures in excess of 2500 K have found evidence for new physical processes at play in their atmospheres.
Here, we investigate the dynamical effects of the dis- sociation of molecular hydrogen and recombination of atomic hydrogen on the atmospheric circulation of ultra-hot Jupiters. To do so, we incorporate these ef- fects into a general circulation model (GCM) for hot Jupiter atmospheres, and run a large suite of mod- els varying the incident stellar flux and strength of frictional drag. We find that including hydrogen dissociation and recombination reduces the day-to- night temperature contrast of ultra-hot Jupiter atmo- spheres and causes the speed of the equatorial jet to decrease. This is because the large energy input re- quired for hydrogen dissociation cools the dayside of the planet, and the energy released due to hydrogen recombination warms the nightside. The associated large heating/cooling rate and the mean molecular weight change modify the wave-mean-flow interac- tions, which likely results in the weaker equatorial jet. The results from our GCM experiments qualita- tively agree with previous theory that the day-night temperature contrast of ultra-hot Jupiters should de- crease due to hydrogen dissociation and recombina- tion. Lastly we compute full-phase light curves from our suite of GCMs, finding that the reduced day-to- night temperature contrast in ultra-hot Jupiter atmo- spheres causes a smaller phase curve amplitude. The reduction in phase curve amplitude due to hydrogen dissociation and recombination could explain the relatively small phase curve amplitudes of observed ultra-hot Jupiters WASP-33b, WASP-103b and KELT- 9b. Our work would first provide valuable under- standing on the basic dynamical processes of ultra- hot Jupiters, helping to interpret future observations of their atmospheres. Secondly our work would stimulate further theoretical investigations, reveal- ing complex interplays between different physical processes in atmospheres of ultra-hot Jupiters.
326.04 — Time Variability in Hot Jupiter Atmo- spheres
Thaddeus Komacek1; Adam Showman2
1 University of Chicago (Chicago, Illinois, United States)
2 Lunar and Planetary Laboratory (Tucson, Arizona, United States) Hot Jupiter atmospheres are expected to be dynamic environments with time-variable large scale circula- tion patterns. However, to date there has been no detection of variability of hot Jupiter atmospheres in the infrared, while the visible light phase curve of HAT-P-7b has been observed to show a periodic oscillation in its phase offset. In this work, we per- form the first study of the expected infrared time- variability of a broad range of hot Jupiter atmo- spheres in preparation for JWST. To do so, we per-
form a large suite of atmospheric circulation mod- els, varying the incident stellar flux and atmospheric drag strength. We place lower limits on the atmo- spheric variability, as we do not include the effects of Lorentz forces, large-scale shear instabilities, and clouds. In general, we find that the amplitude of variability is largest in the equatorial regions and in- creases with increasing incident stellar flux and fric- tional drag strength, both in terms of temperature and emergent flux. We show that JWST will be able to detect variability due to atmospheric circulation in the secondary eclipse depth and may be able to detect variability in the phase curve amplitude and offset. The periodicity and amplitude of detected variability will provide a first-order understanding of the interaction of large-scale standing waves in hot Jupiter atmospheres. Additionally, if variability sig- nificantly larger than expected from our simulations is found, that may provide evidence for additional physical processes (e.g., magnetic effects, clouds) af- fecting the emergent flux of hot Jupiters.
326.05 — Leaking Exoplanets: Understanding how Stars Affect Atmospheric Escape in Exoplanets
Andrew Cleary1; Aline Vidotto1
1 Trinity College Dublin (Dublin, Leinster, Ireland)
The atmospheres of highly irradiated exoplanets are observed to undergo hydrodynamic escape, result- ing in planetary mass loss. However, stellar winds can shape and even prevent atmospheric escape, affecting observable signatures of escape such as Lyman-α and H-α line profiles. In this work, we simulate atmospheric escape of close-in exoplanets and investigate whether they are affected by stellar winds. We show that, although younger hot-Jupiters experience higher levels of atmospheric escape, ow- ing to a favourable combination of higher irradiation levels and weaker planetary gravity, stellar winds are also stronger at this young age, which act to re- duce/inhibit escape rates of young exoplanets.
326.06 — Revisiting the NUV Transmission Spec- trum of HD 209458b: Signs of Ionized Iron Beyond the Roche Lobe
Patricio Cubillos1; Luca Fossati1; Tommi Koskinen3; Mitchell Young1; Kevin France2; Michael Salz4; Aikara
Sreejith1; Carole Haswell5
1 Space Research Institute, Austria (Graz, Austria)
2 Astrophysical and Planetary Science, University of Colorado (Boulder, Colorado, United States)
3 Lunar and Planetary Laboratory, University of Arizona (Tucson, Arizona, United States)
4 Hamburger Sternwarte, Universitaet Hamburg (Hamburg, Ger- many)
5 Department of Physical Sciences, The Open University (Milton Keynes, United Kingdom)
Ultraviolet transit observations probe the upper at- mosphere of exoplanets, where mass loss occurs. Our analysis of the archival HST/STIS NUV trans- mission observations of HD 209458b shows evidence for ionized iron, but no evidence for neutral iron, neutral magnesium, nor ionized magnesium. While our non-detection of neutral magnesium resolves the tension with theoretical models from previous results, our results are at still odds with lower- atmosphere models resulting from optical and in- frared observations. These upper-atmosphere obser- vations indicate that hydrodynamic escape is strong enough to carry heavy atoms like iron beyond the planetary Roche lobe; however, lower-atmosphere observations suggest the presence of cloud conden- sates. With iron-bearing aerosols condensating more strongly than magnesium-bearing aerosols, if mag- nesium is trapped in the lower atmosphere, iron should be as well. The intricate relationship between lower- and upper-atmosphere properties makes the combination UV and optical/infrared observations more valuable than the sum of its individual parts. The unique properties of the HD 209458 system place its transiting hot Jupiter in a pivotal role in our understanding of planetary atmospheres, few other planets will ever enable such precise measurements of both their upper- and lower-atmosphere proper- ties. Here, I will present the analysis and theoretical interpretation of the HD 209458b NUV observations. Then I will discuss the prospects of future observa- tions to elucidate the puzzling nature of this planet’s atmosphere as a whole, which is of particular value before the the imminent launch of the James Webb Space Telescope.
326.07 — Supervised machine learning for inter- preting ground-based, high-resolution transmis- sion spectra of exoplanets
Chloe Fisher1; H. Jens Hoeijmakers1,2; Daniel
Kitzmann1; Simon Grimm1; Pablo Márquez-Neila3;
David Ehrenreich2; Raphael Sznitman3; Kevin Heng1 1 Center for Space and Habitability, University of Bern (Bern, Switzerland)
2 Observatoire astronomique de l’Université de Genève (Geneva, Switzerland)
3 ARTORG Center for Biomedical Engineering, University of Bern (Bern, Switzerland)
We present a novel, unpublished approach to per-
forming atmospheric retrieval on high-resolution ground-based data for exoplanets using supervised machine learning. We have developed a technique that combines the well-established method of cross- correlation with our random forest retrieval algo- rithm.
High-resolution spectroscopy using meter-class, ground-based telescopes has revolutionized our ability to identify atoms and molecules in the at- mospheres of exoplanets. However, the high lev- els of noise and large number of spectral points pro- vide a challenge for traditional methods of retrieval. Currently, detections of molecules are made using the technique of cross-correlation, which matches line positions of atomic and molecular species with the high-resolution absorption spectra. But used on its own, cross-correlation does not yield the pos- terior distribution of the abundance of an atom or molecule, or the properties of the atmosphere being observed.
We introduce a hybrid retrieval method that com- bines the cross-correlation method with a supervised machine learning method using the random forest. It leverages the statistical content of the spectrum to overcome the high level of noise and uses feature engineering to reduce the size of the training set. We use the hybrid method to interpret the HARPS- N transmission spectrum of KELT-9b, deriving pos- terior distributions for the metallicity and temper- ature and demonstrating that it is able to diagnose missing physics in the retrieval. The hybrid method will be decisive for performing retrieval on suites of high-resolution spectra with broad wavelength cov- erage as the next generation of ground-based spec- trographs come online.
326.08 — Modeling disequilibrium chemistry of exoplanet atmospheres using a sequence of post- processed forward models
Robin Baeyens1; Leen Decin1; Ludmila Carone2; Olivia Venot3
1 KU Leuven (Leuven, Belgium)
2 Max-Planck-Institut für Astronomie (Heidelberg, Germany) 3 Laboratoire Interuniversitaire des Systèmes Atmosphériques (Créteil, France)
In anticipation of the next era of space telescopes for exoplanet characterization (James Webb, ARIEL) it is essential that sophisticated modeling tools for the atmospheres of transiting planets are developed. However, the associated effects of strong stellar ir- radiation and tidal locking make these objects in- herently three-dimensional (3D) in nature, and mul- tidimensional forward models are thus required to
accurately simulate the multitude of processes that comprise an atmospheric system. This is especially the case for the out-of-equilibrium chemical compo- sition, which is tightly coupled to the planetary cli- mate through dynamical quenching and can show large longitudinal variations due to day-night tem- perature differences and photochemical reactions. Despite fast developments in the field, coupling 3D general circulation models (GCM) with radiative transfer and chemistry, computation times are a ma- jor bottleneck of these models and thus they are only applied to a small number of planets.
In an effort to remedy this limitation, we employ a range of post-processed forward models in sequence: a 3D GCM (MITgcm, Adcroft+2004) with simpli- fied, Newtonian radiative transfer (based on petit- CODE, Mollière+ 2015), a post-processed pseudo-2D chemical network solver (Agundez+ 2014) and a ray- tracing code (petitRADTRANS, Mollière+ 2019), to compute an extensive grid of planetary atmospheres and synthetic transmission spectra. This allows us to study the mechanisms of disequilibrium chemistry and their effect on the observables in a systematic way for a large range of planets. More specifically, we report on the change in synthetic transmission spectra due to longitudinally-varying vertical mixing and photochemistry. This enables us to derive gen- eral parametrizations for these processes for imple- mentation in 1D retrieval codes, a necessary step in preparing for the interpretation of high-quality data coming from the James Webb Space Telescope and ARIEL.
326.09 — Exoplanet atmosphere characterization with SPIRou: first results for HD 189733b
Anne Boucher1; Antoine Darveau-Bernier1; David Lafrenière1; Romain Allart2; Stefan Pelletier1; Neil Cook1; Étienne Artigau1; Christophe Lovis2; Björn Benneke1; René Doyon1; Claire Moutou3
1 Institute for Research on Exoplanets, Université de Montréal (Montreal, Quebec, Canada)
2 Geneva observatory, University of Geneva (Versoix, Switzerland) 3 Canada-France-Hawaii Telescope (Waimea, Hawaii, United States) SPIRou is the new high-resolution, near-infrared spectro-polarimeter at the Canada-France-Hawaii Telescope. Primarily built to detect earth-like exo- planets around M-dwarfs through precise radial ve- locity measurements, it is also, thanks to its large spectral range (Y to K band) and its high R∼70,000 resolving power, an excellent instrument for exo- planet atmospheric characterization via transit and emission spectroscopy. SPIRou observed its first ex- oplanet transit — of the planet HD 189733b — in
September 2018. I will present preliminary results of this first observation, and of other transits that have been observed since then as part of the SPIRou Legacy Survey. Thus far, we can re-confirm the de- tections of water and metastable helium signals in the transmission spectrum of HD 189733b.
326.10 — Atmospheric Characterization of HD209548 and HD189733 with High Resolution Cross Correlation Spectroscopy
Joseph Zalesky1; Rebecca Webb2; Michael Line1; Matteo
Brogi2
1 Arizona State University (Tempe, Arizona, United States) 2 University of Warwick (Warwick, United Kingdom)
High Resolution Cross Correlation Spectroscopy (HRCCS) has become a powerful tool to constrain both the physical characteristics and abundances of atomic/molecular constituents in exoplanetary at- mospheres. Brogi & Line (2019) recently introduced a novel Bayesian atmospheric retrieval methodol- ogy that can combine observations from both longer wavelength (2-4 micron), ground-based, HRCCS and shorter wavelength (1-2 micron) space-based obser- vatories such as the Hubble Space Telescope (HST). Here we present results from the first application of this technique to both new and previously published observations of HD209458b and HD189733b from VLT/CRIRES, HST, and Spitzer. The more com- plete wavelength coverage provides a more com- prehensive assessment of the atmosphere by way of stronger constraints on the thermal profiles, atmo- spheric metallicity, and carbon/oxygen inventory for these two benchmark planets. We also inves- tigate the impact of possible model-induced biases including assumptions regarding molecular cross- sections, cloud model prescriptions, and thermal profile parameterizations. Finally, we present what constraints may be possible in the future by per- forming retrievals of synthetic observations from the next generation of high-resolution spectrographs like CRIRES+. This work has laid a foundational dataset that combines both space and ground-based observations to comprehensively characterize exo- planetary atmospheres and will be a useful bench- mark in comparison to future efforts for both transit- ing and non-transiting atmospheric characterization.
326.11 — Three-Dimensonal Mixing of Photochem- ical Hazes in the Atmospheres of Hot Jupiters
Maria Elisabeth Steinrueck1; Adam Showman1; Tommi
1 Lunar and Planetary Laboratory, University of Arizona (Tucson, Arizona, United States)
2 Groupe de Spectrométrie Moleculaire et Atmosphérique, Univer- sité de Reims Champagne Ardenne, Reims (Reims, France)
The transmission spectra of many hot Jupiters show signatures of high-altitude aerosols. The nature and composition of these aerosols is unknown— one possible explanation is that they are produced through photochemical processes. Previous studies of photochemical hazes on tidally locked exoplan- ets used one-dimensional models. These 1D mod- els have to make strongly simplifying assumptions about the strength of vertical mixing. Furthermore, they ignore that the strong day-night contrast on hot Jupiters, the spatially varying production rate of photochemical species acting as haze precursors and the interaction with the atmospheric circulation can lead to inhomogeneous aerosol distributions. Gen- eral circulation models (GCMs) are needed to bet- ter understand how photochemical hazes are mixed by the atmospheric circulation, what the resulting 3D aerosol distributions are, and how 1D modelers can make more informed choices to represent 3D processes as accurately as possible in a 1D frame- work. As photochemical hazes are produced at much higher altitudes than condensate clouds and are expected to have small particle sizes, they may interact differently with the atmospheric circulation than condensate clouds.
We present results from GCM simulations of hot Jupiter HD 189733b to explore the mixing of pho- tochemical hazes. With an equilibrium tempera- ture near 1,200 K, this well-studied planet is cool enough that photochemical hazes and condensate