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2010 Rauscher & Menou 2013 Komacek & Showman 2016) or by coupling to the magnetic induction equation (Batygin et al.

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Moreover, the Lorentz forces and ohmic dissipation related to free electrons in weakly ionized atmospheres have been captured to varying degrees of sophistication in GCM frameworks, often as a Rayleigh drag force (e.g., Perna et al. For instance, recent models have incorporated the cooling and heating effects of hydrogen dissociation and recombination (Tan & Komacek 2019 Mansfield et al. To account for the unique 3D properties of ultrahot Jupiters, various updates to “traditional” hot Jupiter general circulation models (GCMs) have been required. 2020) observations, including those at high spectral resolution, which are the subject of this paper. These features make it challenging to justify treating such planets as 1D objects, and the departures from 1D behavior are especially apparent in certain current and future (Feng et al. 2016) these atmospheres’ short chemical timescales relative to dynamical timescales should drive them to chemical equilibrium (Baeyens et al. 2009 Rauscher & Menou 2012 Kataria et al. Such highly irradiated objects are predicted to have very strong day–night temperature gradients, and perhaps chemical gradients, too (e.g., Showman et al. One particularly intriguing aspect of ultrahot Jupiter atmospheres is their three-dimensional (3D) structure. In short, observations of ultrahot Jupiters have revealed them to be sites for extreme physics, consequently requiring significant model updates to understand them in detail. The presence of gas-phase metals at low pressures within these atmospheres also renders ultrahot Jupiters notably susceptible to temperature inversions by virtue of strong optical absorption of host starlight (e.g., Lothringer & Barman 2019). Featuring persistent dayside temperatures in excess of 2200 K, ultrahot Jupiter atmospheres are thought to include thermal dissociation of molecules and thermal ionization of metals. 2018)-has emerged, once again requiring the construction of new theoretical frameworks. In the past five years, however, an even more extreme class of planet-the “ultrahot Jupiter” (Arcangeli et al. 2013 Dobbs-Dixon & Agol 2013 Kataria et al. Our procedure’s success in diagnosing phase-resolved Doppler shifts demonstrates the benefits of physical, self-consistent, 3D simulations in modeling high-resolution spectra of exoplanet atmospheres.ĭecades after the discovery of the first exoplanet (Mayor & Queloz 1995), a harbinger of the population of “hot Jupiters,” observational, theoretical, and laboratory efforts have elucidated some of the key processes and features relevant to these planets (e.g., Showman & Guillot 2002 Cooper 2006 Knutson et al. We additionally validate our forward-modeled spectra by reproducing lines of nearly all species detected in WASP-76b by Tabernero et al. This fit is further improved by allowing a small orbital eccentricity ( e ≈ 0.017), consistent with prior WASP-76b orbital constraints. observations-with marginal contributions from condensation. Instead, we find that high-altitude, optically thick clouds composed of Al 2O 3, Fe, or Mg 2SiO 4 provide reasonable fits to the Ehrenreich et al. However, we cannot reproduce either the magnitude or the time-dependence of the WASP-76b Doppler signature with gas-phase iron condensation alone. We identify low atmospheric drag and a deep radiative-convective boundary as necessary components of our GCM to produce this asymmetry (the latter is consistent with existing Spitzer phase curves). We confirm that a physical mechanism driving strong east–west asymmetries across the terminator must exist to reproduce large Doppler blueshifts in WASP-76b’s transmission spectrum. In this work, we forward model the atmosphere of WASP-76b with double-gray general circulation models (GCMs) and ray-striking radiative transfer to diagnose the planet’s high-resolution transmission spectrum. Interpretations of these observations invoke toy model depictions of gas-phase iron condensation in lower-temperature regions of the planet’s atmosphere. reported transmission spectra from the ESPRESSO spectrograph yielding an anomalously large Doppler blueshift from the ultrahot Jupiter WASP-76b. High-resolution spectra are unique indicators of three-dimensional (3D) processes in exoplanetary atmospheres.

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