JWST Observations of Young protoStars (JOYS). Linked accretion and ejection in a Class I protobinary system
Güdel, Manuel; Le Gouellec, Valentin J. M.; Beuther, Henrik; Tabone, Benoît; Caratti o Garatti, Alessio; van Dishoeck, Ewine F.; Rocha, Will R. M.; Brunken, Nashanty G. C.; Slavicinska, Katerina; Klaassen, Pamela; Kavanagh, Patrick J.; Francis, Logan; Tychoniec, Łukasz; Justtanont, Kay; Perotti, Giulia; van Gelder, Martijn L.; Ray, Thomas P.; Chen, Yuan; Linnartz, Harold; Gieser, Caroline; Devaraj, Rangaswamy; Östlin, Goran
Netherlands, Germany, Italy, Sweden, United States, Ireland, France, United Kingdom, Austria, Switzerland
Abstract
Context. Accretion and ejection dictate the outcomes of star and planet formation processes. The mid-infrared (MIR) wavelength range offers key tracers of processes that have been difficult to detect and spatially resolve in protostars until now.
Aims: 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 at a 85 au separation.
Methods: Using the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) observations in 5-28 μm range, we measured the intensities of emission lines of H2, atoms, and ions, for instance, the [Fe II] and [Ne II], and HI recombination lines. We analyzed the spatial distribution of the different species using the MIRI Medium Resolution Spectrometer (MRS) capabilities to spatially resolve emission at 0″.2-0″.7 scales. we compared these results with the corresponding Atacama Large Millimeter/submillimeter Array (ALMA) maps tracing cold gas and dust.
Results: We detected 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 Eup from S(8) to S(1) rotational transitions, indicating the disk wind as its 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 detected an accretion streamer infalling from > 1000 au scales onto the TMC1-E component. The TMC1-W protostar powers a collimated jet, detected with [Fe II] and [Ni II], making it consistent with energetic flow. A much weaker ionized jet is observed from TMC1-E, and both jets appear strikingly parallel to each other, indicating that the disks are co-planar. TMC1-W is associated with strong emission from hydrogen recombination lines, tracing the accretion onto the young star.
Conclusions: MIRI-MRS observations provide an unprecedented view of protostellar accretion and ejection processes on 20 au scales. 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. Finally, the 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.