Evolution of starless cores in massive clumps seen by the ALMA ASHES and QUARKS surveys

Abstract

We present a systematic comparative analysis of 324 starless cores in early-phase infrared-dark clouds (IRDCs; ASHES survey) and evolved-phase infrared-bright clouds (IRBCs; QUARKS survey) using 1.3 mm continuum and line data by the Atacama Large Millimeter/submillimeter Array. Despite having comparable sizes (∼2500 au), starless cores in IRBCs exhibit systematically higher median mass (1.5 M⊙ versus 0.6 M⊙), number density, and surface density—enhancements of approximately a factor of 2 relative to starless cores in IRDCs. Starless cores in IRBCs also display relatively stronger nonthermal motions (σ ∼ 0.5 km s−1 versus 0.3 km s−1), higher total virial parameters (median αvir,tot ∼ 2.3 versus 1.0), and steeper density profiles, indicating more centrally concentrated structures in feedback-driven, turbulence-enhanced environments. These findings support a dual evolutionary origin: (i) new core formation in evolved IRBCs under altered initial conditions and (ii) subsequent dynamical mass growth via accretion from extended reservoirs. The prevalence of low-mass starless cores—even in late-stage IRBC environments—challenges models requiring massive prestellar cores and instead favors competitive-like dynamical mass accretion scenarios for high-mass star formation.