ALMA ACA and Nobeyama observations of two Orion cores in deuterated molecular lines

Abstract

We mapped two molecular cloud cores in the Orion A cloud with the ALMA ACA 7-m Array and with the Nobeyama 45-m radio telescope. These cores have bright N${}_2$D${}^{+}$ emission in single-pointing observations with the Nobeyama 45-m radio telescope, have relatively high deuterium fraction, and are thought to be close to the onset of star formation. One is a star-forming core, and the other is starless. These cores are located along filaments observed in N${}_2$H${}^{+}$, and show narrow linewidths of 0.41 km s${}^{-1}$ and 0.45 km s${}^{-1}$ in N${}_2$D${}^{+}$, respectively, with the Nobeyama 45-m telescope. Both cores were detected with the ALMA ACA 7m Array in the continuum and molecular lines at Band 6. The starless core G211 shows clumpy structure with several sub-cores, which in turn show chemical differences. Also, the sub-cores in G211 have internal motions that are almost purely thermal. The starless sub-core G211D, in particular, shows a hint of the inverse P Cygni profile, suggesting infall motion. The star-forming core G210 shows an interesting spatial feature of two N${}_2$D${}^{+}$ peaks of similar intensity and radial velocity located symmetrically with respect to the single dust continuum peak. One interpretation is that the two N${}_2$D${}^{+}$ peaks represent an edge-on pseudo-disk. The CO outflow lobes, however, are not directed perpendicular to the line connecting both N${}_2$D${}^{+}$ peaks.

31 pages, 17 figures, 9 tables, to appear in ApJ (accepted April 23, 2020)

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Cited by in corpus (12)

• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP) II. Survey overview: a first look at 1.3 mm continuum maps and molecular outflows
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• Multi-line observations of CH${}_3$OH, c-C${}_3$H${}_2$ and HNCO towards L1544: Dissecting the core structure with chemical differentiation
• Molecular Cloud Cores with High Deuterium Fractions: Nobeyama Mapping Survey
• Characterization of dense Planck clumps observed with Herschel and SCUBA-2
• Nobeyama Survey of Inward Motions toward Cores in Orion Identified by SCUBA-2
• The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE III. The large scale distribution of DCO+, DNC and DCN in the DR21 filament