Salt, Hot Water, and Silicon Compounds Tracing Massive Twin Disks
Artikel i vetenskaplig tidskrift, 2020

We report results of 0.''. 05-resolution observations toward the O-type proto-binary system IRAS 16547-4247 with the Atacama Large Millimeter/submillimeter Array. We present dynamical and chemical structures of the circumbinary disk, circumstellar disks, outflows, and jets, illustrated by multi-wavelength continuum and various molecular lines. In particular, we detect sodium chloride, silicon compounds, and vibrationally excited water lines as probes of the individual protostellar disks at a scale of 100 au. These are complementary to typical hot-core molecules tracing the circumbinary structures on a 1000 au scale. The H2O line tracing inner disks has an upper-state energy of E-u/k > 3000 K, indicating a high temperature of the disks. On the other hand, despite the detected transitions of NaCl, SiO, and SiS not necessarily having high upper-state energies, they are enhanced only in the vicinity of the protostars. We posit that these molecules are the products of dust destruction, which only happens in the inner disks. This is the second detection of alkali metal halide in protostellar systems after the case of the disk of Orion Source I, and also one of few massive protostellar disks associated with high-energy transition water and silicon compounds. These new results suggest that these "hot-disk" lines may be common in innermost disks around massive protostars, and have great potential for future research of massive star formation. We also tentatively find that the twin disks are counter-rotating, which might give a hint of the origin of the massive protobinary system IRAS 16547-4247.


Kei E. I. Tanaka

National Astronomical Observatory of Japan

Osaka University

Yichen Zhang


Tomoya Hirota

The Graduate University for Advanced Studies (SOKENDAI)

National Astronomical Observatory of Japan

Nami Sakai


Kazuhito Motogi

Yamaguchi University

Kengo Tomida

Osaka University

Tohoku University

Jonathan Tan

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

Viviana Rosero

National Radio Astronomy Observatory Socorro

Aya E. Higuchi

National Astronomical Observatory of Japan

Satoshi Ohashi


Mengyao Liu

University of Virginia

Koichiro Sugiyama

National Astronomical Research Institute of Thailand

National Astronomical Observatory of Japan

Astrophysical Journal Letters

2041-8205 (ISSN) 2041-8213 (eISSN)

Vol. 900 1 L2


Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik

Teoretisk kemi



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