Astro Seminar: Marcelo Barraza Alfaro

Speaker: Marcelo Barraza Alfaro (NBI)

Title: Predicting signatures of turbulence in ALMA molecular line observations of protoplanetary disks

Abstract: Gas turbulence significantly affects planet formation and the evolution of protoplanetary disks, yet its origin and strength remain difficult to constrain empirically. In my talk, I will revisit observational diagnostics of turbulence in CO line emission and present recent predictions that account for a wide range of turbulent eddy sizes. These new predictions are obtained by post-processing results from state-of-the-art numerical simulations of disk instabilities. We show that large-scale motions induced by disk instabilities could be detectable with high-resolution ALMA observations, providing observable signatures that can help identify the origin of turbulence in protoplanetary disks. In addition, we demonstrate that the line-broadening signatures of a turbulent cascade differ from those predicted by current disk models used to constrain turbulence strength directly from ALMA observations. In particular, we find that spatially unresolved large-scale turbulent motions can bias constraints on turbulence strength derived from line broadening.