No abstract

The atmospheres of ultra-hot Jupiters are highly interesting and unique chemical laboratories. Due to the very high atmospheric temperatures, their chemical composition is dominated by atoms and ions instead of molecules, and the formation of aerosols on their day-sides is unlikely. Thus, for these planets detailed chemical characterisations via the direct detection of elements through high-resolution day-side and transit spectroscopy are possible. This in principle allows the element abundances of these objects to be directly inferred, which may provide crucial constraints on their formation process and evolution history. In the recent past, several chemical species, mostly in the form of atoms and ions, have already been detected using high-resolution spectroscopy in combination with the cross-correlation technique. As part of the Mantis network, we provide a grid of standard templates in this study, designed to be used together with the crosscorrelation method. This allows for the straightforward detection of chemical species in the atmospheres of hot extrasolar planets. In total, we calculate high-resolution templates for more than 140 different species across several atmospheric temperatures. In addition to the high-resolution templates, we also provide line masks that just include the position of line peaks and their absorption depths relative to the spectral continuum. A separate version of these line masks also takes potential blending effects with lines of other species into account. All templates and line masks are publicly available on the CDS data server.

Radiative transfer (RT) is a key component for investigating atmospheres of planetary bodies. With the 3D nature of exoplanet atmospheres being important in giving rise to their observable properties, accurate and fast 3D methods are required to be developed to meet future multidimensional and temporal data sets. We develop an open-source GPU RT code, gCMCRT, a Monte Carlo RT forward model for general use in planetary atmosphere RT problems. We aim to automate the post-processing pipeline, starting from direct global circulation model (GCM) output to synthetic spectra. We develop albedo, emission, and transmission spectra modes for 3D and 1D input structures. We include capability to use correlated-k and high-resolution opacity tables, the latter of which can be Doppler-shifted inside the model. We post-process results from several GCM groups, including ExoRad, SPARC/MITgcm THOR, UK Met Office UM, Exo-FMS, and the Rauscher model. Users can therefore take advantage of desktop and HPC GPU computing solutions. gCMCRT is well suited for post-processing large GCM model grids produced by members of the community and for high-resolution 3D investigations.

<p>Ultra-hot Jupiters form a new class of exoplanets that tend to orbit hot early type stars in short periods, and may be heated to temperatures much greater than 2,000K on their day-sides. The extreme temperature dissociates all but the most strongly bound molecules and a significant fraction of the atomic gas may be thermally ionised. Under these circumstances, line absorption lines by metals and some molecules are dominant sources of short-wave opacity, causing strong thermal inversions. These inversions have consequences for atmospheric chemistry, as well as global circulation of gas and heat. Excitingly, due to the highly elevated temperatures, thermal inversion layers cause strong emission lines, that can be observed using high-resolution spectroscopy. This allows the chemical and thermal structure of the atmospheric to be constrained, in principle in three dimensions. </p> <p> </p> <p>Previous transit observations of the ultra-hot Jupiter WASP-121 b have revealed a rich spectrum of various metals, including iron and vanadium, but with a notable absence of titanium and titanium-oxide, which may be depleted due to condensation processes. In this talk I will present our recent observations of the emission spectrum of the planet’s dayside, which, beside showing a collection of emitting metals, provide strong direct evidence of the fate of titanium-bearing species on the cooler night-side of the planet (Fig. 1).</p> <p> </p> <p> </p> <p><strong>Fig. 1:</strong></p> <p><img src="" alt="" /></p> <p> </p> <p> </p>

The atmospheres of ultra hot Jupiters (UHJs) are prime targets for the detection of molecules and atoms at both low and high spectral resolution. We study the atmospheres of the UHJs WASP-121b and WASP-189b by performing 3D general circulation models (GCMs) of these planets using high temperature correlated-k opacity schemes with ultra-violet (UV) absorbing species included. The GCM results are then post-processed at low and high spectral resolutions and compared to available data. The high resolution results are cross-correlated with molecular and atomic templates to produce mock molecular detections. Our GCM models produce similar temperature-pressure (T-p) structure trends to previous 1D radiative-convective equilibrium models of UHJs. Furthermore, the inclusion of UV opacities greatly shapes the thermal and dynamical properties of the high-altitude, low-pressure regions of the UHJ atmospheres, with sharp T-p inversions due to the absorption of UV light. This suggests that optical wavelength, high-resolution observations probe a dynamically distinct upper atmospheric region, rather than the deeper jet forming layers.