Exoplanets and Stellar Physics

Abstract:

The ExoMol database (www.exomol.com) provides molecular data for spectroscopic studies of hot atmospheres. These data are widely used to model atmospheres of exoplanets, cool stars and other astronomical objects, as well as a variety of terrestrial applications. The 2024 data release reports the current status of the database which contains recommended line lists for 91 molecules and 224 isotopologues giving a total of almost 10$^{12}$ individual transitions. New features of the database include extensive "MARVELization" of line lists to allow them to be used for high resolutions studies, extension of several line lists to ultraviolet wavelengths, provision of photodissociation cross sections and extended provision of broadening parameters. Some of the in-house data specifications have been rewritten in JSON and moved to conformity with other international standards. Data products, including specific heats, a database of lifetimes for plasma studies, and the ExoMolHR web app which allows exclusively high resolution data to be extracted, are discussed

Abstract:

ABSTRACT We present results of 3D hydrodynamical simulations of HD209458b including a coupled, radiatively active cloud model (eddysed). We investigate the role of the mixing by replacing the default convective treatment used in previous works with a more physically relevant mixing treatment (Kzz) based on global circulation. We find that uncertainty in the efficiency of sedimentation through the sedimentation factor fsed plays a larger role in shaping cloud thickness and its radiative feedback on the local gas temperatures – e.g. hotspot shift and day-to-night side temperature gradient – than the switch in mixing treatment. We demonstrate using our new mixing treatments that simulations with cloud scales that are a fraction of the pressure scale height improve agreement with the observed transmission spectra, the emission spectra, and the Spitzer 4.5 µm phase curve, although our models are still unable to reproduce the optical and ultraviolet transmission spectra. We also find that the inclusion of cloud increases the transit asymmetry in the optical between the east and west limbs, although the difference remains small ($\lesssim 1{{\ \rm per\ cent}}$).