JWST Observations of Young protoStars (JOYS)

Author(s): A. Caratti O Garatti, T. P. Ray, P. J. Kavanagh, M. J. McCaughrean, C. Gieser, T. Giannini, E. F. Van Dishoeck, K. Justtanont, M. L. Van Gelder, L. Francis, H. Beuther, L. Tychoniec, B. Nisini, M. G. Navarro, R. Devaraj, S. Reyes, P. Nazari, P. Klaassen, M. Güdel, Th Henning, P. O. Lagage, G. Östlin, B. Vandenbussche, C. Waelkens, G. Wright
Abstract: Context. Due to the high visual extinction and lack of sensitive mid-infrared (MIR) telescopes, the origin and properties of outflows and jets from embedded Class 0 protostars are still poorly constrained. Aims. We aim to characterise the physical, kinematic, and dynamical properties of the HH 211 jet and outflow, one of the youngest protostellar flows. Methods. We used the James Webb Space Telescope (JWST) and its Mid-InfraRed Instrument (MIRI) in the 5-28 μm range to study the embedded HH 211 flow. We mapped a 0′.95 × 0′.22 region, covering the full extent of the blueshifted lobe, the central protostellar region, and a small portion of the redshifted lobe. We extracted spectra along the jet and outflow and constructed line and excitation maps of both atomic and molecular lines. Additional JWST NIRCam H₂ narrow-band images (at 2.122 and 3.235 μm) provide a visualextinction map of the whole flow, and are used to deredden our data. Results. The jet-driving source is not detected even at the longest MIR wavelengths. The overall morphology of the flow consists of a highly collimated jet, which is mostly molecular (H₂, HD) with an inner atomic ([Fe I], [Fe II], [S I], [Ni II]) structure. The jet shocks the ambient medium, producing several large bow shocks (BSs) that are rich in forbidden atomic ([Fe II], [S I], [Ni II], [Cl I], [Cl II], [Ar II], [Co II], [Ne II], [S III]) and molecular lines (H₂, HD, CO, OH, H₂O, CO₂, HCO⁺), and is driving an H₂ molecular outflow that is mostly traced by low- J, v = 0 transitions. Moreover, H₂ 0-0 S(1) uncollimated emission is also detected down to 2″-3″ (~650-1000 au) from the source, tracing a cold (T=200-400 K), less dense, and poorly collimated molecular wind. Two H₂ components (warm, T =300-1000 K, and hot, T =1000-3500 K) are detected along the jet and outflow. The atomic jet ([Fe II] at 26 μm) is detected down to ~130 au from the source, whereas the lack of H₂ emission (at 17 μm) close to the source is likely due to the large visual extinction (A_V > 80 mag). Dust-continuum emission is detected at the terminal BSs and in the blue- and redshifted jet, and is likely attributable to dust lifted from the disc. Conclusions. The jet shows an onion-like structure, with layers of different size, velocity, temperature, and chemical composition. Moreover, moving from the inner jet to the outer BSs, different physical, kinematic, and excitation conditions for both molecular and atomic gas are observed. The mass-flux rate and momentum of the jet, as well as the momentum flux of the warm H₂ component, are up to one order of magnitude higher than those inferred from the atomic jet component. Our findings indicate that the warm H₂ red component is the main driver of the outflow, that is to say it is the most significant dynamical component of the jet, in contrast to jets from more evolved YSOs, where the atomic component is dominant.
Organisation(s): Department of Astrophysics
External organisation(s): INAF Astronomical Observatory of Capodimonte , Dublin Institute for Advanced Studies, National University of Ireland, Maynooth, Max-Planck-Institut für Astronomie, Max-Planck-Institut für extraterrestrische Physik, INAF - Osservatorio Astronomico di Roma, Leiden University, Chalmers University of Technology, European Southern Observatory (Germany), The Royal Observatory, Edinburgh, Eidgenössische Technische Hochschule Zürich, Université Paris Saclay, Oskar Klein Centre, Katholieke Universiteit Leuven
Journal: Astronomy and Astrophysics
Volume: 691
No. of pages: 29
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202451350
Publication date: 11-2024
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103004 Astrophysics
Keywords
ASJC Scopus subject areas: Astronomy and Astrophysics, Space and Planetary Science
Portal url: https://ucrisportal.univie.ac.at/en/publications/dc27c012-8c58-4c20-b435-15c52b74f75b

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