Latest insights on dust evolution


Contact : Ugo Lebreuilly et Valentin Le Gouellec

General description of the workshop :

Dust grains are essential components of the interstellar medium (ISM), as they play a central role in a myriad of astrophysical and astrochemical processes. Because dust grains re-irradiate in the infra-red a significant part of the energy emitted as starlight, they control cooling and heating rates of star forming regions (Weingartner & Draine 2001, Draine 2004). This makes them crucial actors in the regulation of star formation, which is one of the main agents governing the evolution of galaxies. Dust grains are also central for the molecular chemistry of the ISM, with the formation of H2 happening on their surface (e.g. Le Bourlot et al. 2012) and the formation of complex organic molecules happening within ices surrounding their cores (Jorgensen 2020). The assembly of dust in favorable environments, such as protoplanetary disks, leads to the formation of pebbles and planetesimals, which are the precursors of planets (Testi 2014). Finally, the dynamical role of magnetic fields in dense star forming environments is strongly dependent on the size distribution of dust grains (Zhao et al., 2016). This, in turn, can control the outcome of the formation of stars, disks and planets.


Several mechanisms control the evolution of the dust properties (size distribution, shape, chemical composition, structure, and porosity) in the ISM. To this day, their theoretical understanding and experimental/observational probes are still incomplete. Various effects (coagulation, grain sputtering, shattering, vaporization, rotational disruption, photo-fragmentation) can regulate the dust grains size distribution (Guillet et al. 2007, Hoang et al. 2019, Schirmer et al. 2022, Lebreuilly et al. 2023).  The formation of PAHs from very small carbonaceous grains can occur in various environments (Nozawa et al 2003, Berné et al. 2007, Schneider et al. 2014). Under the right circumstances, grains can also decouple dynamically from the gas leading to dust-to-gas ratio variations (e.g. Lebreuilly et al. 2020). Finally, different grain processing mechanisms affect their crystallinity and chemical composition (e.g., photolysis, nucleation, aromatisation, dehydrogenation).


Improving our knowledge related to dust properties in the different environments of the ISM, in order to better understand the physical and chemical mechanisms associated, is a challenge of great importance. To this end, significant developments have been operated recently in the community, offering new observing and modeling tools, as well as new laboratory results. The aim of this workshop is to bring together the French community around these questions and address the relevant problems gathering different disciplines: dust observations (extinction, emission, scattering, absorption), the laboratory experiments (spectral signatures, optical properties, outcome of collisions) and dust evolution modelisation (growth, dynamics, feedback processes) in simulations of different environments. Building bridges between these disciplines and the teams’ expertise is key to enable large progress in this domain.

Confirmed invited speakers :  Olivier Berné, Guillaume Laibe & François Ménard.

Contributed talks :

In addition to the reviews, some slots are available for contributed talks. We strongly encourage PhD students and post-doctoral researchers to apply for a presentation. Abstracts can be submitted at the following link : https://journees.sf2a.eu

Preliminary program :

Theory and numerical experiments
Review 1 (20'+5')
Contributed (10'+5')
Contributed (10'+5')
Contributed (10'+5')
Contributed (10'+5')
Observation and laboratory experiments
Review 2 (20'+5')
Review 3 (20'+5')
Contributed (10'+5')
Contributed (10'+5')
Contributed (10'+5')