Project description
Shedding light on the enigmatic whirl of dust and gas from which planets are formed
Spinning around nascent stars are flattened disc-like clouds of gas and dust (circumstellar disks) believed to be the origins of planetary systems. Modern telescopes have captured crescents, spirals and winds within the discs, suggesting things are pretty nonlinear in there. However, recent evidence suggests they may actually exhibit very low turbulence due to the small fraction of charged particles and thus poor coupling to the magnetic field. Current understanding is based on crude modelling of the hypothetical magneto-hydrodynamic forces (related to the magnetic properties of the ionised gas) guiding the formation and evolution of these discs. The EU-funded MHDiscs project is developing advanced models integrating self-organising principles and magnetothermal winds as additional drivers of circumstellar disc evolution to enhance our understanding of planetary formation.
Objective
Circumstellar discs are the birthplaces of planets. They form around young protostars and dissipate in a few million years. Modern submillimeter and optical telescopes such as ALMA and VLT/SPHERE are now able
to resolve thin structures in the bulk of these objects, such as rings, crescents, spirals and winds, probing the very origin of planetary systems similar to our own. Our current understanding of these discs relies on a very crude modelling of a hypothetic magneto-hydrodynamic (MHD) turbulence thought to play an essential role in the evolution and structure of these systems. However, there is now compelling theoretical and observational evidence that these discs are weakly turbulent, if not laminar, because of their low ionisation fraction and thus poor coupling to the magnetic field. This suggests that subtle MHD processes are driving the dynamics of these objects.
Moreover, my recent theoretical breakthroughs demonstrate that these gaseous discs are subject to self-organisation and magneto-thermal winds. These processes play a key role for the disc as they can control its radial structure and evolution. I propose that computing global non-ideal MHD models from massively parallel numerical simulations will shed a new light on these processes, connecting the long-term evolution of these discs to the formation of large scale structures seen by ALMA and SPHERE. We expect MHDiscs to provide reliable global evolution models by coupling gas dynamics to dust and irradiation. These models will be used to predict discriminant observables of the processes I propose, setting the stage for a deeper understanding of the formation of planetary systems.
Fields of science
Programme(s)
Funding Scheme
ERC-COG - Consolidator GrantHost institution
75794 Paris
France