Impeding Turbulence Decay in Self-gravitating Cloud Cores
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arXiv
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| Autori principali: | , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866909782907027456 |
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| author | Yuan, Shibo Li, Hua-Bai |
| author_facet | Yuan, Shibo Li, Hua-Bai |
| contents | Turbulence governs the fragmentation of molecular clouds and plays a pivotal role in star formation. The persistence of observed cloud turbulence suggests it does not decay significantly within the turnover timescale, implying a recurrent driving mechanism. Although ubiquitous self-gravity is a plausible driver, MHD simulations by \citet{ostriker2001density} demonstrated that self-gravity alone does not modify the global turbulence decay rate. In this study, we demonstrate that the dominant diffuse volume of a cloud dictates its overall decay rate, while individual dense cores can maintain near-zero decay rates. Crucially, this phenomenon is absent in control simulations excluding self-gravity. This discrepancy cannot be attributed to contamination of turbulent velocities by core contraction, as most cores in our simulations remain in a quasi-equilibrium state. Our analysis reveals that the gravitational potential energy released during core formation\textemdash not necessarily driven by self-gravity but also by turbulent compression\textemdash is sufficient to sustain the observed turbulence levels within cores. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_15476 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Impeding Turbulence Decay in Self-gravitating Cloud Cores Yuan, Shibo Li, Hua-Bai Astrophysics of Galaxies Turbulence governs the fragmentation of molecular clouds and plays a pivotal role in star formation. The persistence of observed cloud turbulence suggests it does not decay significantly within the turnover timescale, implying a recurrent driving mechanism. Although ubiquitous self-gravity is a plausible driver, MHD simulations by \citet{ostriker2001density} demonstrated that self-gravity alone does not modify the global turbulence decay rate. In this study, we demonstrate that the dominant diffuse volume of a cloud dictates its overall decay rate, while individual dense cores can maintain near-zero decay rates. Crucially, this phenomenon is absent in control simulations excluding self-gravity. This discrepancy cannot be attributed to contamination of turbulent velocities by core contraction, as most cores in our simulations remain in a quasi-equilibrium state. Our analysis reveals that the gravitational potential energy released during core formation\textemdash not necessarily driven by self-gravity but also by turbulent compression\textemdash is sufficient to sustain the observed turbulence levels within cores. |
| title | Impeding Turbulence Decay in Self-gravitating Cloud Cores |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2506.15476 |