Oral title: Chemical probes in protoplanetary disks: 14N/15N ratio in HCN

Oral abstract: The chemical composition of planets is directly linked to that of protoplenetary disks. In particular, the comparison of 
isotopic ratios in Solar system bodies and in Solar analogs can help to understand the origin of the material, which remains an 
open question. I will present ALMA observations of H13CN and HC15N in a diverse set of 7 disks, and show the radial dependence 
of 14N/15N in one disk.