Nitrogen isotopic ratio across the Galaxy through observations of high-mass star-forming cores

Abstract

There is a growing evidence that our Sun was born in a rich cluster that also contained massive stars. Therefore, the study of high-mass star-forming regions is key to understand our chemical heritage. In fact, molecules found in comets, in other pristine Solar System bodies and in protoplanetary disks, are enriched in 15N, because they show a lower 14N/15N ratio (100-150) with respect to the value representative of the Proto-Solar Nebula (PSN, 441 ± 6), but the reasons of this enrichment cannot be explained by current chemical models. Moreover, the 14N/15N ratio is important because from it we can learn more about the stellar nucleosynthesis processes that produces both the elements. In this sense observations of star-forming regions are useful to constrain Galactic chemical evolution (GCE) models.