Issue |
A&A
Volume 695, March 2025
|
|
---|---|---|
Article Number | A145 | |
Number of page(s) | 15 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361/202452475 | |
Published online | 18 March 2025 |
The H2 jet and disk wind of the Class I protostar HOPS 315
Leiden Observatory, Leiden University,
PO Box 9513,
2300
RA Leiden, The Netherlands
★ Corresponding author; stijnvleugels@gmail.com
Received:
3
October
2024
Accepted:
19
February
2025
Context. Protostellar outflows are important to many areas of star formation. They enable protostars to build mass by removing angular momentum from accreting material, mix hot solids into the comet-forming regions of young disks, and they provide chemical feedback to star-forming molecular clouds. However, the launching mechanisms of protostellar outflows at early ages are still debated. HOPS 315, a young Class I protostar known to exhibit a purely molecular H2 jet, provides an interesting case to constrain launching models.
Aims. We aim to investigate the physical structure, kinematics, and spatial distribution of the outflowing material of HOPS 315 to constrain its components and their launching mechanism.
Methods. We analyse spatially resolved JWST MIRI and NIRSpec spectra of HOPS 315 and perform Gaussian fits to rotational and ro-vibrational H2 emission lines. By constructing rotation diagrams in each spaxel, we map the morphology, velocity, temperature, and ortho-to-para ratio (OPR) in the outflow.
Results. We find that the mid-infrared 0–0 S(1)–S(5) rotational H2 emission traces a wide-angle wind component, which peaks along the jet axis, while near-infrared ro-vibrational H2 emission traces the collimated jet. The wind exhibits velocities ≳20 km s−1, temperatures of 500–600 K, and an OPR of 3. We estimate a terminal velocity of 120–125 km s−1 for the jet and a temperature of 2400–3800 K. The OPR in the jet decreases from 3 near the protostar to 2.49−0.030.03 by 500 au from the protostar.
Conclusions. Our observations may be explained by an magneto-hydrodynamic (MHD) disk wind, wide-angled wind-driven outflows, or jet bow shock-driven outflows. The ortho-to-para disequilibrium in the jet possibly results from grain surface ortho-to-para conversion reactions in the inner disk. The presence of disk winds at this age is potentially consistent with theories of radial transport of hot material to the comet-forming regions of the Solar System.
Key words: stars: jets / stars: winds, outflows / ISM: individual objects: HOPS 315
© The Authors 2025
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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