Rivers in the sky: streamers as catalysts for physical and chemical changes in protostars and disks

Streamers, infalling gaseous structures ranging from a few hundred to over 10,000 astronomical units, have been identified as a new method of supplying material to protostellar and protoplanetary disks, thanks to recent high-resolution observations with ALMA and NOEMA. To date, about 30 streamers have been discovered at various stages of star formation. However, the full impact of these ``rivers in the sky'' on our understanding of star and planet formation remains unclear. It is still uncertain which molecules best trace these structures, and the effects of this infall on the disk itself and its interaction with the protostar are just beginning to be investigated using high-resolution ALMA observations. In this presentation, I'll share our most recent findings about streamers, particularly from the NOEMA large program PRODIGE. I'll discuss their impact on the physical and chemical conditions of the disk, and explore the new and exciting possibilities the ALMA WSU will open. ALMA is a critical tool for detecting these structures, and the increased bandwidth and quicker integration times will help us identify the most effective streamer-tracing molecules, examine the shocks generated at their landing sites in disks, and potentially reveal their structure in dust emission.