Christian Rab, Kapteyn Astronomical Institute (University of Groningen, NL) - 4.11.19
High spatial resolution observations have revealed stunning ring and gap features in the dust emission of planet-forming disks. Those gaps likely trace ongoing planet formation, but it is not clear yet if each gap hosts a planet or if other mechanisms, such as ice lines or magnetised disks also play a role. Measuring the gas properties within the dust gaps can constrain the origin of the gap as, for example, (massive) planets would also produce deep gas gaps.
I will briefly discuss a few examples of current ALMA molecular line observations to show the richness of gas observations but also the challenges in interpreting them. One prominent example is the disk around the Herbig Ae/Be star HD 163296. We use high-quality ALMA data (DSHARP) to model the disk of HD 163296 with the 2D radiation thermochemical disk code ProDiMo (PROtoplanetary DIsk MOdel). We self-consistently model the dust and gas structure, considering chemistry and detailed heating/cooling, and produce synthetic observables that allow for a direct comparison to observations. Such models provide constraints on the radial gas und dust structure of the disk, information crucial for planet formation theories.
Furthermore, I will discuss the potential of ALMA to detect the gas disks around wide-orbit (>100 au) planetary-mass companions and to measure the rotation profile of their disks. Such observations can provide stringent constraints on the mass of the companions and show if they are planets.