Abstract

The measurement of rotation curves led to big discoveries in astronomy, like the proposition of dark matter halos around galaxies. With the emergence of ALMA , it is now similarly possible to measure the rotation of gas in protoplanetary disks, which are several orders of magnitude smaller than galaxies. While the overall motion of the gas around newborn stars is Keplerian, with high spectral resolution molecular line observations, we can trace small-scale velocity perturbations caused by local pressure variations in the disk, possibly due to embedded planets. In the talk, I will discuss how we can observe gas rotation in planet-forming disks and what we can learn from studying the deviations from Keplerian rotation. In particular, I will present results from the rotation curve study for the disks of the exoALMA Large Program. We find that substructures in the deviation from Keplerian rotation are ubiquitous in our sample, on both small and large scales, and can reach up to 15 percent in the most extreme cases. Interestingly, the majority of the dust continuum rings and gaps are co-located with pressure maxima and minima, respectively. Finally, I will compare the presented results with the predictions from the theory and put them into the bigger picture of planet formation.