Walsh, C orcid.org/0000-0001-6078-786X, Millar, TJ and Nomura, H (2010) CHEMICAL PROCESSES IN PROTOPLANETARY DISKS. The Astrophysical Journal, 722 (2). pp. 1607-1623. ISSN 0004-637X
Abstract
We have developed a high-resolution combined physical and chemical model of a protoplanetary disk surrounding a typical T Tauri star. Our aims were to use our model to calculate the chemical structure of disks on small scales (submilliarcsecond in the inner disk for objects at the distance of Taurus, ~140 pc) to investigate the various chemical processes thought to be important in disks and to determine potential molecular tracers of each process. Our gas-phase network was extracted from the UMIST Database for Astrochemistry to which we added gas-grain interactions including freezeout and thermal and non-thermal desorption (cosmic-ray-induced desorption, photodesorption, and X-ray desorption), and a grain-surface network. We find that cosmic-ray-induced desorption has the least effect on our disk chemical structure while photodesorption has a significant effect, enhancing the abundances of most gas-phase molecules throughout the disk and affecting the abundances and distribution of HCN, CN, and CS, in particular. In the outer disk, we also see enhancements in the abundances of H2O and CO2. X-ray desorption is a potentially powerful mechanism in disks, acting to homogenize the fractional abundances of gas-phase species across the depth and increasing the column densities of most molecules, although there remain significant uncertainties in the rates adopted for this process. The addition of grain-surface chemistry enhances the fractional abundances of several small complex organic molecules including CH3OH, HCOOCH3, and CH3OCH3 to potentially observable values (i.e., a fractional abundance of gsim10–11).
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2010. The American Astronomical Society. All rights reserved. Reproduced in accordance with the publisher's self-archiving policy. Published online; http://doi.org/10.1088/0004-637X/722/2/1607 |
Keywords: | Astrochemistry; ISM: molecules; Protoplanetary disks; Stars: formation |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 11 Jul 2019 08:29 |
Last Modified: | 11 Jul 2019 08:29 |
Status: | Published |
Publisher: | American Astronomical Society |
Identification Number: | 10.1088/0004-637X/722/2/1607 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:107146 |