arXiv subjects

Jessica Cmiel

Publications and source records attributed to Jessica Cmiel.

3 recordsLinked to original sources

arXiv2026

Climates of temperate rocky planets with He-dominated atmospheres

We present radiative-convective modeling of rocky exoplanets with $He$-dominated atmospheres and low envelope mass fractions. Helium has a steeper adiabatic temperature profile than $N_2$ and $H_2$ as it has fewer degrees of freedom. Line broadening differences are small, collision-induced absorption (CIA) is not important in $He$-dominated atmospheres, and Rayleigh scattering by $He$ is weak. The combined impact of these effects is that $He$-dominated atmospheres provide more warming than $N_2$-dominated atmospheres but less than $H_2$-dominated atmospheres, for the same surface pressure. For surface pressures in the range 1-20 bar, the habitable zone for rocky planets around M dwarfs with $He$-dominated atmospheres is narrower than for $H_2$-dominated atmospheres. Nonetheless, due to their large scale height compared to $N_2$ or $CO_2$-dominated atmospheres, temperate $He$-dominated atmospheres are favorable targets for characterization via transit spectroscopy with JWST.

astro-ph.EP↗

arXiv2025

Coupled atmospHere Interior modeL Intercomparison (CHILI) Protocol Version 1.0: A CUISINES Intercomparison Project of Magma Ocean Models

Spectroscopic characterization of rocky exoplanets with the James Webb Space Telescope has brought the origin and evolution of their atmospheres into the focus of exoplanet science. Time-evolved models of the feedback between interior and atmosphere are critical to predict and interpret these observations and link them to the Solar System terrestrial planets. However, models differ in methodologies and input data, which can lead to significant differences in interpretation. In this paper, we present the experimental protocol of the Coupled atmospHere Interior modeL Intercomparison (CHILI) project. CHILI is an (exo-)planet model intercomparison project within the Climates Using Interactive Suites of Intercomparisons Nested for Exoplanet Studies (CUISINES) framework, which aims to support a diverse set of multi-model intercomparison projects in the exoplanet community. The present protocol includes the initial set of participating magma ocean models, divided into evolutionary and static models, and two types of test categories, one focused on Solar System planets (Earth & Venus) and the other on exoplanets orbiting low-mass M-dwarfs. Both test categories aim to quantify the evolution of key markers of the links between planetary atmospheres and interiors over geological timescales. The proposed tests would allow us to quantify and compare the differences between coupled atmosphere-interior models used by the exoplanet and planetary science communities. Results from the proposed tests will be published in dedicated follow-up papers. To encourage the community to join this comparison effort and as an example, we present initial test results for the early Earth and TRAPPIST-1 b, conducted with models differing in the treatment of energy transport in the planetary interior and atmosphere, surface boundary layer, geochemistry, and the in- and outgassing of volatile compounds.

astro-ph.EP↗

arXiv2025

Characterizing the Radiative-Convective Structure of Dense Rocky Planet Atmospheres

We use a one-dimensional line-by-line radiative-convective model to simulate hot, dense terrestrial-planet atmospheres. We find that strong shortwave absorption by H2O and CO2 inhibits near-surface convection, reducing surface temperatures by up to approximately 2000 K compared to fully convective predictions. Pure CO2 atmospheres are typically 1000 K cooler than pure H2O atmospheres, with only a few percent of H2O needed to elevate surface temperatures by hundreds of kelvin for a fixed incident stellar radiation. We also show that minor greenhouse gases such as SO2 and NH3 have a limited warming effect when H2O is abundant. Even at insolation values as high as 12,500 W/m2 (about 37 times Earth's current solar flux), planets with mixed CO2-H2O envelopes have surface temperatures in the 1200 to 2000 K range, limiting surface melting. Our results highlight the critical role of shortwave heating on magma ocean planets and the need for improved high-temperature spectroscopy beyond 20,000 cm-1.

astro-ph.EP↗