The ALMA-ATOMS-QUARKS Survey: Resolving a Chemically Rich Massive Protostellar Outflow

Abstract

Abstract We present a comprehensive study on the physical and chemical structures of a chemically rich bipolar outflow in a high-mass star-forming region IRAS 16272−4837 (SDC335), utilizing high-resolution spectral line data at 1.3 and 3 mm dual bands from the Atacama Large Millimeter/submillimeter Array, ATOMS, and QUARKS surveys. The high-velocity jet is enveloped by a lower-velocity outflow cavity, containing bright knots that show enhanced molecular intensities and elevated excitation temperatures. Along the outflow, we have identified 35 transitions from 22 molecular species. By analyzing the spatial distribution and kinematics of these molecular lines, we find that the molecular inventory in the outflow is regulated by three processes: (i) direct entrainment from the natal molecular core by the outflow; (ii) shock-induced release of molecules or atoms from dust grains; and (iii) thermal desorption and gas-phase reactions driven by shock heating. These results confirm that outflows are not only dynamical structures but also active chemical factories, where entrainment, shocks, and thermal processing jointly enrich the molecular content. Our findings confirmed that outflow chemistry has a multiorigin nature, and provide critical insights into chemical evolution during high-mass star formation.

Affiliated Institutions

• Kyushu University JP
• University of Chile CL
• Chinese Academy of Sciences CN
• Xinjiang Astronomical Observatory CN
• National Astronomical Observatories CN
• Eötvös Loránd University HU
• University of Debrecen HU
• Korea Astronomy and Space Science Institute KR
• Shanghai Astronomical Observatory CN
• University of Chinese Academy of Sciences CN
• S.N. Bose National Centre for Basic Sciences IN
• Tsinghua University CN
• Kavli Institute for Theoretical Sciences CN
• Korea University of Science and Technology KR
• Universidad Católica del Norte CL
• University of Oslo
• The University of Tokyo JP
• Peking University CN
• Max Planck Institute for Astronomy DE
• Yunnan University CN

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