A misaligned protostellar disk fed by gas streamers in a barred spiral-like massive dense core
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High-mass stars, born in massive dense cores (MDCs), play a major role in the cosmic ecosystem. Yet, little is known about how MDCs assemble their mass beyond ∼0.1 pc and transport their mass into smaller and denser seeds of stellar embryos (∼100 au) and finally onto HighMass Young Stellar Objects (HMYSOs), which is the key to understand the high-mass star formation processes. Leveraging multi-scale observations at 40–2500 au resolutions toward an MDC with at least one HMYSO associated, we discovered a dynamical system analogous to the barred spiral structures in galaxies. It shows three prominent ∼20,000 au long spiral arms feeding a bar-like elongated structure (∼7,500 au, hereafter denoted as “bar”) at the center. The “bar” further transports gas to a disk through gas streamers. The pseudodisk (>2,000 au) revealed in methanol thermal emission, the Keplerian disk (∼500 au) traced by Class II methanol masers, and the inner disk (∼100 au) traced by long-baseline (0.03 ′′ ) 1.3 mm continuum emission are misaligned. A collimated bipolar outflow is detected launching from the HMYSO. These dynamical features highlight the multi-scale mass accretion through well-organized hierarchical structures during the formation of HMYSOs. Our discovery manifests that this “spirals-bar-disk-outflow” complex exists not only in galaxies as a whole but also in the galactic localized regions where high-mass stars form. The structures and dynamics of galaxies could provide stimulating insights into high-mass star formation, and vice versa.
