AI Insight
This study uses the STARFORGE simulation suite to track how gas evolves from giant molecular clouds into individual stars across different magnetic field strengths. Researchers found that low-mass stars form quickly from compact gas regions over approximately 0.5 million years, while high-mass stars accrete material from much larger volumes over 3-4 million years. The gas properties before star formation resemble observed dense cores and are primarily regulated by turbulence, though high-mass stars show intermittent accretion patterns that existing theoretical models cannot fully explain.
Why it matters
Understanding how gas collects and evolves into stars of different masses is fundamental to explaining stellar population distributions in galaxies and the chemical evolution of the universe. The findings that turbulence plays a dominant role over magnetic fields in regulating star formation could refine models used to predict star formation rates in various cosmic environments.
arXiv:2604.06471v2 Announce Type: replace
Abstract: Star formation occurs within dense regions of giant molecular clouds (GMCs), however, exactly how gas collects and evolves to form individual stars and what role dense cores play remains unclear. We use the Lagrangian cell information in the STARFORGE simulation suite to track star-forming gas in three GMCs with varying magnetic field strengths. We find that, once a protostar forms, the lifetime of the unaccreted gas correlates with the final stellar mass, where low-mass stars ($M_*$ 2 M$_odot$) accrete over 3.3-4.7 Myr from a much larger volume. Although the protostellar accretion time increases weakly with magnetic field strength, the accreting gas radii, velocity dispersions, virial parameters, and magnetic energy ratios are largely insensitive to the global cloud properties. At the time of protostar formation, the unaccreted gas exhibits linewidth-size and mass-size relations characteristic of turbulently regulated, isothermal dense cores, following $sigma_v propto R^{0.47-0.55}$ and $M propto R^{1.0-1.1}$, respectively. Low- and intermediate-mass stars undergo relatively continuous accretion and their accretion histories are well-fit by either isothermal sphere, turbulent core, or competitive accretion models, where no one model fits all masses. However, many high-mass stars experience intermittent accretion and their accretion histories are not well-fit by any of these models. While the distribution of accreting gas is more extended than typically-defined dense cores, the physical properties and structure of the star-forming gas resemble those of observed cores and are largely regulated by turbulence and feedback.
Source: The Evolution of Star-Forming Gas in STARFORGE: From Clouds, to Cores, to Stars