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Summary
The L328 core has three sub-cores, S1, S2, and S3, with S2 containing L328-IRS, a Very Low Luminosity Object (VeLLO). The core-scale magnetic field (B-field) strength is estimated to be 50.5±9.8μG, indicating that B-fields are getting stronger on smaller scales.
Highlights
- The L328 core has three sub-cores: S1, S2, and S3.
- S2 contains L328-IRS, a Very Low Luminosity Object (VeLLO).
- The core-scale magnetic field (B-field) strength is estimated to be 50.5±9.8μG.
- The B-field strength in the core is approximately 2.5 times higher than in the envelope.
- The mass-to-flux ratio of 1.1±0.2 suggests that the core is magnetically transcritical.
- The energy budget in the L328 core reveals that gravitational, magnetic, and non-thermal kinetic energies are comparable, while thermal energy is significantly lower.
- The polarisation fraction decreases with increasing intensity in the high-density region, indicating depolarisation in the core.
Key Insights
- The L328 core's magnetic field is well-connected from cloud to core scales, indicating that the core is embedded in a strong B-field region.
- The estimated B-field strength within the L328 core is significantly higher than in the envelope, suggesting that B-fields are getting stronger on smaller scales.
- The core and envelope are found to be transcritical and marginally supercritical, respectively, with a mass-to-flux ratio of 1.1±0.2 and 1.3±0.6.
- The non-thermal kinetic energy, gravitational energy, and magnetic energy are comparable to each other, while the thermal kinetic energy is significantly lower, indicating that the core's dynamics are influenced by both magnetic and turbulent forces.
- The polarisation fraction decreases with increasing intensity in the high-density region, indicating depolarisation in the core, which can be caused by changes in B-field orientation, grain growth, or magnetic reconnection.
- The L328 core's energy budget and magnetic field properties suggest that it is in a state of dynamic equilibrium, with magnetic and turbulent forces counteracting the gravitational pull, potentially delaying or regulating the collapse process.
- The comparison with other VeLLOs and starless cores suggests that magnetic supercriticality may be linked to the presence of IRS sources or imminent collapse, highlighting the importance of magnetic fields in the star formation process.
Mindmap
Citation
Gupta, S., Soam, A., Karoly, J., Lee, C. W., & G, M. (2024). Magnetic fields on different spatial scales of the L328 cloud (Version 1). arXiv. https://doi.org/10.48550/ARXIV.2412.19701