AI Insight
This paper introduces TRINITY, a new computational model that simulates how massive stars disperse their parent molecular clouds through stellar winds, radiation pressure, and photoionization before supernova explosions occur. The researchers found that photoionized gas pressure increases the expanding shell radius by approximately 17% and that the initial structure of the molecular cloud significantly affects whether it disperses, re-collapses, or allows ionizing photons to escape. Specifically, clouds with steeper density profiles continue expanding while shallower or uniform clouds tend to re-collapse, even when stellar populations are identical.
Why it matters
Understanding cloud dispersal mechanisms is crucial for explaining star formation efficiency and the escape of ionizing radiation from galaxies. This model provides a computationally efficient tool to predict how different cloud conditions respond to stellar feedback, which has implications for interpreting multi-wavelength astronomical observations and understanding galaxy evolution.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Abstract: Multi-wavelength surveys place cloud dispersal at 1-5 Myr after massive stars emerge, before the first supernovae. Whether a cloud disperses, re-collapses, or leaks Lyman-continuum (LyC) photons depends on how pre-supernova winds, radiation pressure, and photoionised-gas pressure ($P_{rm HII}$) couple to the shell. We introduce TRINITY, a 1D thin-shell code that succeeds WARPFIELD. TRINITY evolves the bubble-shell structure under winds, supernovae, direct and dust-reprocessed radiation pressure, $P_{rm HII}$, and gravity. A phase-aware prescription drives the shell with the larger of the hot-bubble and photoionised pressures when energy-driven, and $P_{rm HII}$ plus ram pressure when momentum-driven. The initial cloud may be uniform, a piecewise power law, or a Bonnor-Ebert sphere; shell structure, hot-bubble cooling, photon absorption, and LyC escape evolve with the dynamics. We validate against analytic wind and photoionisation limits and survey clouds of mass $10^5$-$10^{6.5},M_odot$, core density $10^3$-$10^4$ cm$^{-3}$, and star-formation efficiency $varepsilon=0.01$-$0.30$. $P_{rm HII}$ enlarges the shell radius by roughly 17% at 10 Myr in the fiducial run. At higher efficiency, the energy-driven phase lasts under 1 Myr, radiation pressure stays sub-dominant, and $P_{rm HII}$ remains dynamically important in the momentum-driven phase. Cloud structure sets both phase durations and outcomes: at fixed mass, core density, and efficiency, homogeneous and shallow clouds re-collapse while a steep $rhopropto r^{-2}$ cloud keeps expanding, and Bonnor-Ebert clouds disperse roughly 55% later than homogeneous ones. Thus $P_{rm HII}$ and cloud structure both shape feedback-driven expansion even when the stellar population is fixed. TRINITY is an efficient, interpretable framework to map feedback dominance across cloud parameter space and resolved H II regions.