Radial variations in nitrogen, carbon, and hydrogen fractionation in the PDS 70 planet-hosting disk

Recent exoplanetary studies revealed a broad diversity in the exoplanetary population, suggesting that the outcomes of planet formation are similarly diverse. Footprints of the journey of building blocks of planets are stored in exoplanetary atmospheres, which are the result of a complex chemical evolution from the parental cloud down to protoplanetary disks. In particular, isotopic ratios of the main elements (hydrogen, carbon, nitrogen, oxygen) are powerful tracers of the formation history of planetary material. While isotopic ratios have been measured for a variety of astronomical objects along the timeline of planet formation, a complete study of isotope fractionation at the protoplanetary disk stage is still missing. I will present ALMA high resolution line emission observations of the PDS 70 disk, which is the best source where to test the chemical link between forming planets and their natal environment, as it is the only disk with two multi-wavelength directly detected protoplanets. Thanks to the unprecedented spatial resolution, I will show radially resolved 14N/15N, 12C/13C, and H/D ratios extracted from HCN isotopologues observations. In particular, radial variations of fractionation levels reveal how different fractionation processes dominate at different planet-forming scales. In this context, I will show how the presence of two giant protoplanets affects the radial profiles of isotopic ratios in a planet-hosting disk.