Effects of accretion flow on the chemical structure in the inner regions of protoplanetary disksH. Nomura1, Y. Aikawa2, Y. Nakagawa2, and T. J. Millar1
1 Astrophysics Research Centre, School of Mathematics & Physics, Queen's University Belfast, Belfast BT7 1NN, UK
2 Department of Earth and Planetary Sciences, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501, Japan
Received 16 May 2008 / Accepted 22 October 2008
Aims. We study the dependence of the profiles of molecular abundances and line emission on the accretion flow in the hot (100 K) inner region of protoplanetary disks.
Methods. The gas-phase reactions initiated by evaporation of the ice mantle on dust grains are calculated along the accretion flow. We focus on methanol, a molecule that is formed predominantly by the evaporation of warm ice mantles, to demonstrate how its abundance profile and line emission depend on the accretion flow.
Results. Our results indicate that some evaporated molecules retain high abundances only when the accretion velocity is sufficiently high, and that methanol could be useful as a diagnostic of the accretion flow by means of ALMA observations at the disk radius of 10 AU.
Key words: accretion, accretion disks -- line: formation -- molecular processes -- planetary systems: protoplanetary disks
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