Emergence of high-mass stars in complex fiber networks (EMERGE) V. From filaments to spheroids: the origin of the hub-filament systems

Identified as parsec-size, gas clumps at the junction of multiple filaments, hub-filament systems (HFS) play a crucial role during the formation of young clusters and high-mass stars. These HFS appear nevertheless to be detached from most galactic filaments when compared in the mass-length (M-L) phase-space. We aim to characterize the early evolution of HFS as part of the filamentary description of the interstellar medium. Combining previous scaling relations with new analytic calculations, we created a toy model to explore the different physical regimes described by the M-L diagram. Despite its simplicity, our model accurately reproduces several observational properties reported for filaments and HFS such as their expected typical aspect ratio (\(A\)), mean surface density (\(\Sigma\)), and gas accretion rate (\(\dot{m}\)). Moreover, this model naturally explains the different mass and length regimes populated by filaments and HFS, respectively. Our model predicts a dichotomy between filamentary (\(A\geq 3\)) and spheroidal (\(A