Dottorato - PhD thesis
Area Tematica: RSN 2: Stelle, popolazioni stellari e mezzo interstellare - RSN3: Sole e Sistema Solare - RSN 3: Sole e Sistema Solare
Referente: Stavro L. Ivanovski (
Titolo: (Exo)planetary atmospheres: the formation and impact of Clouds on Hot and Temperate environments
Decorrenza: 19.05.2025
Studying how electromagnetic radiation propagates through different media is central to astrophysics. One of its key applications is the study of planetary atmospheres, both within and beyond the Solar System. Atmospheric radiative transfer models are typically tasked not only with simulating radiation transport but also with determining the temperature profile along the propagation path of the traversed gas, which influences the final outgoing spectrum via the emission term. To achieve this, additional processes such as convection and condensation must be considered, transforming the relatively narrow task of solving the radiative transfer equation into the broader challenge of fully modeling the physics of the atmospheric column.
One area of radiative transfer that still lacks a satisfactory treatment is the role of suspended particulates, namely clouds and hazes. This issue is twofold. First, the microphysics of cloud formation is not yet fully understood, leading to significant uncertainties about where clouds form and what properties they exhibit. Second, accurately modeling the reflection and absorption of radiation by clouds still relies on computationally intensive methods, limiting their widespread integration into radiative transfer pipelines. Since clouds affect a wide range of planetary properties (e.g., Bond albedo) and processes (e.g., the greenhouse effect and the sequestration of elements into non-observable phases), improving their modeling has far-reaching implications, from understanding hot Jupiter formation and migration to searching for biosignatures on temperate rocky planets.
EOS (Simonetti et al. 2022) is an extension of the HELIOS radiative transfer model (Malik et al. 2017), developed at INAF-OATs for studying both gas giant and terrestrial-type atmospheres. EOS has also been coupled with a simplified climate model (ESTM, Vladilo et al. 2015; Biasiotti et al. 2022) and used by the same group to investigate surface conditions on Early Mars, Archean Earth, and several potentially habitable exoplanets (Simonetti et al. 2024; Biasiotti et al. 2024, 2025). However, EOS currently lacks a physically consistent treatment of clouds, which are instead represented at the climate model level using a highly simplified, temperature-dependent parameterization.
The PhD student will work on incorporating clouds into the EOS code in a physically consistent manner. Through this work, the student will gain robust expertise in radiative transfer modeling and develop the numerical skills necessary to integrate cloud physics into GPU-accelerated software. Specifically, the project has three main goals:
- Deriveaset of first-principles conditions for cloud formation within the atmospheric
- Establishalink between the physical conditions in the atmosphere and key cloud properties, such as particle size distribution.
- Implementtheeffects of Mie scattering and absorption by condensate particulates into the EOS radiative transfer code.
Once validated, the enhanced modeling framework and updated code will be used to address longstanding open questions in planetary science, such as the Faint Young Sun Paradox and the role of clouds in the temperature anomalies observed in hot and ultra-hotJupiters.
This research will be conducted within the “Planetary Systems and Origin of Life” group at INAF– Osservatorio Astronomico di Trieste (S. Ivanovski, L. Biasiotti, L. Calderone, F. Dogo, S. Monai, P. Simonetti and G. Vladilo).
