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Published January 2021 | Erratum + Submitted + Published
Journal Article Open

The TW Hya Rosetta Stone Project. I. Radial and Vertical Distributions of DCN and DCO⁺

Abstract

Molecular D/H ratios are frequently used to probe the chemical past of solar system volatiles. Yet it is unclear which parts of the solar nebula hosted an active deuterium fractionation chemistry. To address this question, we present 0farcs2–0farcs4 Atacama Large Millimeter/submillimeter Array (ALMA) observations of DCO⁺ and DCN 2–1, 3–2, and 4–3 toward the nearby protoplanetary disk around TW Hya, taken as part of the TW Hya Rosetta Stone project, augmented with archival data. DCO⁺ is characterized by an excitation temperature of ~40 K across the 70 au radius pebble disk, indicative of emission from a warm, elevated molecular layer. Tentatively, DCN is present at even higher temperatures. Both DCO⁺ and DCN present substantial emission cavities in the inner disk, while in the outer disk the DCO⁺ and DCN morphologies diverge: most DCN emission originates from a narrow ring peaking around 30 au, with some additional diffuse DCN emission present at larger radii, while DCO⁺ is present in a broad structured ring that extends past the pebble disk. Based on a set of simple parametric disk abundance models, these emission patterns can be explained by a near-constant DCN abundance exterior to the cavity, and an increasing DCO⁺ abundance with radius. In conclusion, the ALMA observations reveal an active deuterium fractionation chemistry in multiple disk regions around TW Hya, but not in the cold planetesimal-forming midplane and in the inner disk. More observations are needed to explore whether deuterium fractionation is actually absent in these latter regions, and if its absence is a common feature or something peculiar to the old TW Hya disk.

Additional Information

© 2020. The American Astronomical Society. Received 2020 July 31; revised 2020 October 11; accepted 2020 November 2; published 2020 December 22. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.00311.S and ADS/JAO.ALMA#2016.1.00440.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. This work is supported by the National Radio Astronomy Observatory (NRAO). NRAO is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This work was supported by an award from the Simons Foundation (SCOL # 321183, KÖ). K.I.Ö. also gratefully acknowledges support from the David and Lucille Packard Foundation. L.I.C. gratefully acknowledges support from the David and Lucille Packard Foundation and the Johnson & Johnson WISTEM2D Award. J.B.B. acknowledges support from NASA through the NASA Hubble Fellowship grant #HST-HF2-51429.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. J.T.v.S. and M.R.H. are supported by the Dutch Astrochemistry II program of the Netherlands Organization for Scientific Research (648.000.025). J.H. acknowledges that support for this work was provided by NASA through the NASA Hubble Fellowship grant #HST-HF2-51460.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. C.W acknowledges financial support from the University of Leeds and from the Science and Technology Facilities Council (grant Nos. ST/R000549/1 and ST/T000287/1). J.K.C. acknowledges support from the National Science Foundation Graduate Research Fellowship under Grant No. DGE 1256260 and the National Aeronautics and Space Administration FINESST grant, under Grant No. 80NSSC19K1534. Facility: ALMA - Atacama Large Millimeter Array. Software: CASA (McMullin et al. 2007), Astropy (Astropy Collaboration et al. 2013, 2018), RADMC-3D (Dullemond 2012).

Errata

Erratum: In the published article, there was an error in the code used to generate Figure 5, which resulted in approximately a factor of 3 higher column density than is shown in the corrected figure below. The column density profile values were not discussed in the published article, and this error therefore did not propagate into other parts of the article or affect the article conclusions. Citation: Karin I Öberg et al 2022 AJ 164 169. DOI 10.3847/1538-3881/ac8d0d

Attached Files

Published - Oberg_2021_AJ_161_38.pdf

Submitted - 2011-06774.pdf

Erratum - Oberg_2022_AJ_164_169-ERRATUM.pdf

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Additional details

Created:
October 3, 2023
Modified:
October 24, 2023