JWST Observations of Young protoStars (JOYS): Linked accretion and ejection in a Class I protobinary system

Accretion and ejection sets the outcome of the star and planet formation process. The mid-infrared wavelength range offers key tracers of those processes that were difficult to detect and spatially resolve in protostars until now. We aim to characterize the interplay between accretion and ejection in the low-mass Class I protobinary system TMC1, comprising two young stellar objects: TMC1-W and TMC1-E with 85 au separation. With the James Webb Space Telescope (JWST) - Mid-Infrared Instrument (MIRI) observations in 5 - 28 m range, we measure intensities of emission lines of H₂, atoms and ions, e. g. , Fe II and Ne II, and HI recombination lines. We detect H₂ outflow coming from TMC1-E, with no significant H₂ emission from TMC1-W. The H₂ emission from TMC1-E outflow appears narrow and extends to wider opening angles with decreasing Eₔ₏ from S (8) to S (1) rotational transitions, indicating a disk wind origin. The outflow from TMC1-E protostar shows spatially extended emission lines of Ne II, Ne III, Ar II, and Ar III, with their line ratios consistent with UV radiation as a source of ionization. With ALMA, we detect accretion streamer infalling from > 1000 au scales onto the TMC1-E component. TMC1-W protostar powers a collimated jet, detected with Fe II and Ni II consistent with energetic flow. A much weaker ionized jet is observed from TMC1-E. TMC1-W is associated with strong emission from hydrogen recombination lines, tracing the accretion onto the young star. Observations of a binary Class I protostellar system show that the two processes are clearly intertwined, with accretion from the envelope onto the disk influencing a wide-angle wind ejected on disk scales, while accretion from the protostellar disk onto the protostar is associated with the source launching a collimated high-velocity jet within the innermost regions of the disk.