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Title: A Detailed View of the Circumstellar Environment and Disk of the Forming O-star AFGL 4176
Authors: Johnston, K. G.
Hoare, M. G.
Beuther, H.
Linz, H.
Boley, P.
Kuiper, R.
Kee, N. D.
Robitaille, T. P.
Issue Date: 2020
Publisher: Institute of Physics Publishing
Citation: A Detailed View of the Circumstellar Environment and Disk of the Forming O-star AFGL 4176 / K. G. Johnston, M. G. Hoare, H. Beuther, et al. — DOI 10.3847/1538-4357/ab8adc // Astrophysical Journal. — 2020. — Vol. 896. — Iss. 1. — 35.
Abstract: We present a detailed analysis of the disk and circumstellar environment of the forming O-type star AFGL 4176 mm1, placing results from the Atacama Large Millimeter/submillimeter Array (ALMA) into context with multiwavelength data. With ALMA, we detect seventeen 1.2 mm continuum sources within 5″ (21,000 au) of AFGL 4176 mm1. We find that mm1 has a spectral index of 3.4 0.2 across the ALMA band, with >87% of its 1.2 mm continuum emission from dust. The source mm2, projected 4200 au from mm1, may be a companion or a blueshifted knot in a jet. We also explore the morphological differences between the molecular lines detected with ALMA, finding 203 lines from 25 molecules, which we categorize into several morphological types. Our results show that AFGL 4176 mm1 provides an example of a forming O-star with a large and chemically complex disk, which is mainly traced by nitrogen-bearing molecules. Lines that show strong emission on the blueshifted side of the disk are predominantly oxygen-bearing, which we suggest are tracing a disk accretion shock. The molecules C34S, H2CS, and CH3CCN trace a slow wide-angle wind or dense structures in the outflow cavity walls. With the Australia Telescope Compact Array (ATCA), we detect a compact continuum source (<2000 760 au) at 1.2 cm, associated with mm1, of which >96% is from ionized gas. The ATCA NH3(1, 1) and (2, 2) emission traces a large-scale (r ∼ 0.5 pc) rotating toroid with the disk source mm1 in the blueshifted part of this structure offset to the northwest. © 2020. The American Astronomical Society. All rights reserved..
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85087417557
PURE ID: 13391242
ISSN: 0004637X
DOI: 10.3847/1538-4357/ab8adc
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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