There are large variations in the stable isotope composition of the volatile elements hydrogen, nitrogen, and oxygen among the solar system bodies. The solar system solids are typically enriched in the rare heavy isotopes (D, 15N, 17O, 18O) compared to the Sun and Jupiter. To understand the origin of these isotopic anomalies, a cross-disciplinary link between the fields of astronomy, cosmochemistry, and solar system science is indispensable. However, establishing such as link is not straightforward, as astronomical observations mainly target the gas in star-forming regions, whereas the most pristine solar system materials are present in the form of meteorites and cometary ices. The ratio of the two stable nitrogen isotopes, 14N/15N, is a promising tool for linking results across the fields, as the nitrogen isotopic composition can be measured in star-forming regions and solar system bodies. The 14N/15N ratio should also be less prone to secondary alteration than the deuterium-to-hydrogen ratio.In this contribution, we will present spatially resolved measurements of the 14N/15N ratio around embedded protostars from IRAM observations and the Protostellar Interferometric Line Survey (PILS) with ALMA. First results on the nitrogen isotopic composition of comet 67P/Churyumov-Gerasimenko by Rosetta-ROSINA will also be presented, and we will explain how we are trying to link these data sets to gain insights into the origin of nitrogen in our solar system and beyond.< Réduire