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Atmospheric escape driven by extreme ultraviolet (EUV) radiation is a critical process shaping the evolution of close-in exoplanets. Recent observations have detected helium triplet absorption in numerous (>20) close-in exoplanets,…
We present initial attempts to include the multi-dimensional nature of radiation transport in hydrodynamical simulations of the small-scale structure that arises from the line-driven instability in hot-star winds. Compared to previous 1D or…
We present in this paper the numerical treatment of the coupling between hydrodynamics and radiative transfer. The fluid is modeled by classical conservation laws (mass, momentum and energy) and the radiation by the grey moment $M_1$…
Studying the atmospheres of exoplanets is one of the most promising ways to learn about distant worlds beyond our solar system. The composition of an exoplanet's atmosphere can provide critical insights into its geology and potential…
The transport of CO2 across the air-water interface is central to physical oceanography and carbon sequestration. A comprehensive understanding of this process requires high-resolution diagnostics of diffusion, absorption, and reaction…
Atmospheres play a crucial role in planetary habitability. Around M dwarfs and young Sun-like stars, planets receiving the same insolation as the present-day Earth are exposed to intense stellar X-rays and extreme-ultraviolet (XUV)…
A numerical scheme is proposed for the solution of the three-dimensional radiative transfer equation with variable optical depth. We show that time-dependent ray tracing is an attractive choice for simulations of astrophysical ionization…
We explore the application of Monte Carlo transport methods to solving coupled radiation-hydrodynamics problems. We use a time-dependent, frequency-dependent, 3-dimensional radiation transport code, that is special relativistic and includes…
Context: The thermal and chemical structures of the upper atmospheres of planets crucially influence losses to space and must be understood to constrain the effects of losses on atmospheric evolution. Aims: We develop a 1D first-principles…
Carbon dioxide (CO$_2$) sequestration in saline aquifers has been introduced as one of the most practical, long-term, and safe solutions to tackle a growing threat originating from the emission of CO$_2$. Successfully executing and planning…
Emission line fluxes from cool stars are widely used to establish an apparent emission measure distribution, Emd-app(Te), between temperatures characteristic of the low transition region and the low corona. The true emission measure…
Exploring diverse planetary atmospheres requires modeling tools that are both accurate and flexible. Here, we develop a three-dimensional general circulation model (3D GCM) that for the first time uses a line-by-line approach to describe…
Absorption lines from water, methane and carbon monoxide are detected in the atmosphere of exoplanet HR8799b. A medium-resolution spectrum presented here shows well-resolved and easily identified spectral features from all three molecules…
Partial frequency redistribution (PRD), describing the formation of the line profile, has negligible observational effects for optical depths smaller than ~10^3, at the resolving power of most current instruments. However, when the spectral…
We investigate the impact on convective numerical simulations of thermo-compositional diabatic processes. We focus our study on simulations with a stabilizing temperature gradient and a destabilizing mean-molecular weight gradient. We aim…
We present here an efficient numerical scheme for solving the non-relativistic 1D radiation-hydrodynamics equations including inelastic Compton scattering, which is not included in most codes and is crucial for solving problems such as…
We study numerical methods for dissipative particle dynamics (DPD), which is a system of stochastic differential equations and a popular stochastic momentum-conserving thermostat for simulating complex hydrodynamic behavior at mesoscales.…
UV absorption cross sections are an essential ingredient of photochemical atmosphere models. Exoplanet searches have unveiled a large population of short-period objects with hot atmospheres, very different from what we find in our solar…
Future telescopes will characterize rocky exoplanets in reflected light, revealing their albedo, which depends on surface, cloud, and atmospheric properties. Identifying these features is crucial for assessing habitability. We present…
High spectral resolution transmission spectroscopy is a powerful tool to characterize exoplanet atmospheres. Especially for hot Jupiters, this technique is highly relevant, due to their high altitude absorption e.g. from resonant sodium (Na…