The Post-Rosetta Understanding of the Fate of Cometary Dust

International audienceThanks to its long duration, the Rosetta mission has provided a unique insight into the properties of dust particles released by 67P/C-G nucleus, and ascertained the links between cometary dust and CP-IDPs or UCAMMs [1]. Minerals to organics proportions are quite comparable within the refractory phase, in which carbon-bearing compounds present high-molecular masses [2-4]. Dust particles consist of aggregates of smaller grains and present hierarchical structures, with morphologies ranging from extremely porous to almost compact [5-7].The refractory materials released in comae (monitored with ≈ 4-1.2 au solar distance range for 67P/C-G), subjected to gravitational and non-gravitational forces, build up dust tails and trails, and progressively become parts of the zodiacal cloud, i.e. the lenticular-shaped interplanetary dust cloud. The small dust particles spiral towards the Sun under Poynting-Robertson effect, with migration times in the 300-50000 years range for micron-sized grains with densities about 100-1000 kg m-3 released at solar distances about 4-1.2 au [8]. Such dust particles happen to encounter the Earth atmosphere. Independent approaches have established that most of the near-Earth interplanetary dust comes from Jupiter Family comets, such as 67P/C-G [9-11], which orbit in the vicinity of the ecliptic plane.Updates of our present understanding of dust in 67P/C-G will be proposed. Through various numerical and experimental simulations [e.g. 12], the changes in composition and in physical properties of cometary dust particles in the interplanetary dust cloud will be discussed, as a function of time and of solar distance. The possible implications, for the early evolution of terrestrial planets, of the properties of the cometary dust component in the interplanetary dust cloud will be tentatively addressed.1. Levasseur-Regourd et al. SSR 2018. 2. Goesmann et al. Science 2015. 3. Fray et al. Nature 2016. 4. Bardyn et al. MNRAS 2017. 5. Bentley et al. Nature 2016. 6. Langevin et al. Icarus 2016. 7. Mannel et al. MNRAS 2017. 8. Saïagh PhD Thesis UPE 2014. 9. Lasue et al. Astron. Astrophys. 2007. 10. Nesvorny et al. ApJ 2010. 11. Rowan-Robinson and May MNRAS 2013. 12. Hadamcik et al. PSS 2018