The ODYSSey team aims at investigating the dynamical processes that drive the evolution of protoplanetary disks. The variety of exoplanetary systems has to be accounted for from the initial conditions prevailing in the circumstellar disks. In particular, the assumption of axisymmetry has to be relaxed in order to fully address the complex large-scale structure of primordial disks.
The first ALMA observations of protoplanetary disks in the millimeter range (Marel 2013) have shown strongly non-axisymmetric structures that prompt a new consideration of dynamical evolutionary processes. It is often assumed that forming planets interacting with the disk may be at the origin of these large-scale structures. If correct, the characterization of the disk structures may lead to the discovery of planetary systems in the process of formation, while they are still embedded in the disk. This topics is actively pursued in the ODYSSey team, by performing high-angular resolution imaging of disks from the infrared (SPHERE) to the millimeter domain (ALMA, NOEMA), and by developing numerical models of dust and gas evolution coupled to radiative transfer tools (MCFOST).
Disk asymmetries are also present are small scales, notably close to the inner disk edge, at a few 0.1 AU from the central star. Photometric monitoring campaigns (e.g., the CoRoT/Spitzer CSI 2264 campaign ; cf. Cody et al. 2014) have revealed a rich variety of light curves. Of these, many are due to the obscuration of the central star by dusty clumps located in the inner rotating disk. The physical processes that drive the complex 3D structure of the inner disk, such as star-disk magnetospheric interaction and/or embedded inner planets, still need to be fully elucidated and modeled. This is the one of the goals pursued in the ODYSSey team, with an approach that combines spectropolarimetric measurements of surface magnetic fields in young stars (ESPADONS), and spectro-interferometric imaging of the disk’s inner regions (PIONIER/VLTI, CHARA).
Numerical models provide some clues on the origin of large-scale disk asymmetries (e.g. Turner et al. 2014). Thus, gas vortices can result from the barocline instability (Lesur & Papaloizou 2010) while self-organized turbulence may also lead to zonal flows that favors the formation of large-scale structures (Kunz 2013).