Circumstellar Dust Distribution in Systems with Two Planets in Resonance.

Protoplanetary discs are the fundamental channel to peer into both star formation and planet formation: their study through the combination of theory, observations and numerical simulations is essential to unveil still unanswered questions about their structure and the processes that rule them. ALMA and SPHERE are among the most powerful instrumentation for observations of the cold universe, which open up the opportunity of studying objects like dust discs surrounding young stars. This new generation of imaging has led to major changes in the understanding of protoplanetary discs, which are now acknowledged to have different, complex structures. The mutual interaction between gas, dust, planets and their surroundings leads to deviations from axisymmetric shapes, like gaps, spirals and warps. In my thesis I investigated via numerical simulations the effects of two giant planets locked in resonance on the dust distribution of the circumstellar disc around a young star, in order to gather if such systems are able to leave peculiar features such as a common gap, which is an essential requirement for outward migration — invoked to explain the observed position of several giant exoplanets with respect to their host star (Walsh et al. 2011). In my work I tested the outcome of the variations of some parameters, i.e. the eccentricity of the planets, the scale height of the disc and the equation of state: in particular, I aimed to show the differences produced by the inclusion of viscous heating and radiative transfer. I used the tridimensional code PLUTO (Mignone et al. 2007) and tested its efficiency in simulating the gaseous and dusty components of the disc. The main results I obtained are that gaps in both gas and dust are more easily formed in a locally isothermal disc with a lower scale height and with planets on eccentric orbits: radiative transfer acts as an obstruction for gap forming and dust accretion.