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Carbon-grain Sublimation: A New Top-down Component of Protostellar Chemistry

van ’t Hoff, Merel L. R. and Bergin, Edwin A. and Jørgensen, Jes K. and Blake, Geoffrey A. (2020) Carbon-grain Sublimation: A New Top-down Component of Protostellar Chemistry. Astrophysical Journal Letters, 897 (2). Art. No. L38. ISSN 2041-8213. doi:10.3847/2041-8213/ab9f97.

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Earth's carbon deficit has been an persistent problem in our understanding of the formation of our solar system. A possible solution would be the sublimation of carbon grains at the so-called soot line (~300 K) early in the planet-formation process. Here, we argue that the most likely signatures of this process are an excess of hydrocarbons and nitriles inside the soot line, and a higher excitation temperature for these molecules compared to oxygen-bearing complex organics that desorb around the water snowline (~100 K). Such characteristics have been reported in the literature, for example, in Orion KL, although not uniformly, potentially due to differences in the observational settings and analysis methods of different studies or the episodic nature of protostellar accretion. If this process is active, this would mean that there is a heretofore unknown component to the carbon chemistry during the protostellar phase that is acting from the top down—starting from the destruction of larger species—instead of from the bottom up from atoms. In the presence of such a top-down component, the origin of organic molecules needs to be re-explored.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
van ’t Hoff, Merel L. R.0000-0002-2555-9869
Bergin, Edwin A.0000-0003-4179-6394
Jørgensen, Jes K.0000-0001-9133-8047
Blake, Geoffrey A.0000-0003-0787-1610
Additional Information:© 2020 The American Astronomical Society. Received 2020 May 6; revised 2020 June 18; accepted 2020 June 20; published 2020 July 14. We would like to thank the referee and Ewine van Dishoeck for positive feedback that has improved this paper. M.L.R.H. acknowledges support from the Michigan Society of Fellows. E.A.B. acknowledges funding from NSF grant AST 1907653 and NASA grant XRP 80NSSC20K0259. J.K.J. acknowledges support by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program through ERC Consolidator Grant "S4F" (grant agreement No. 646908). G.A.B. acknowledges support from the NASA XRP (NNX16AB48G) and Astrobiology (NNX15AT33A) programs.
Group:Astronomy Department
Funding AgencyGrant Number
Michigan Society of FellowsUNSPECIFIED
European Research Council (ERC)646908
Subject Keywords:Astrochemistry ; Protostars
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Astrochemistry (75); Protostars (1302)
Record Number:CaltechAUTHORS:20200714-101419102
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Official Citation:Merel L. R. van 't Hoff et al 2020 ApJL 897 L38
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104376
Deposited By: Tony Diaz
Deposited On:14 Jul 2020 17:24
Last Modified:16 Nov 2021 18:31

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