2023ApJ...945...81J

G10.21-0.31 is a 70 μm dark high-mass starless core (M > 300 M_⊙ within r < 0.15 pc) identified in the Spitzer, Herschel, and APEX continuum surveys, and is believed to harbor the initial stages of high-mass star formation. We present Atacama Large Millimeter/submillimeter Array (ALMA) and Submillimeter Array observations to resolve the internal structure of this promising high-mass starless core. Sensitive high-resolution ALMA 1.3 mm dust continuum emission reveals three cores of mass ranging within 11-18 M_⊙, characterized by a turbulent fragmentation. Cores 1, 2, and 3 represent a coherent evolution of three different stages, characterized by outflows (CO and SiO), gas temperature (H₂CO), and deuteration (N₂D⁺/N₂H⁺). We confirm the potential for formation of high-mass stars in G10.21 and explore the evolution path of high-mass star formation. Yet, no high-mass prestellar core is present in G10.21. This suggests a dynamical star formation where cores grow in mass over time.