Issue A&A Volume 506, Number 3, November II 2009 Page(s) 1199 - 1213 Section Interstellar and circumstellar matter DOI 10.1051/0004-6361/200912068 Published online 18 August 2009

A&A 506, 1199-1213 (2009)
DOI: 10.1051/0004-6361/200912068

The inner rim structures of protoplanetary discs

M. Kama¹, M. Min^{1, 2}, and C. Dominik<sup>1, 3

1</sup>  Anton Pannekoek Astronomical Institute, University of Amsterdam, PO Box 94249, 1090 GE Amsterdam, The Netherlands
    e-mail: M.Kama@uva.nl
²  Utrecht Astronomical Institute, University of Utrecht, PO Box 80000, 3508 TA Utrecht, The Netherlands
³  Department of Astrophysics, Radboud University Nijmegen, Postbus 9010, 6500 GL Nijmegen, The Netherlands

Received 13 March 2009 / Accepted 27 July 2009

Abstract
The inner boundary of protoplanetary discs is structured by the dramatic opacity changes at the transition from the dust-containing to a dust-free zone. This paper explores the variety and limits of inner rim structures in passively heated dusty discs. For this study, we implemented detailed sublimation physics in a fast Monte Carlo radiative transfer code. We show that the inner rim in dusty discs is not an infinitely sharp wall but a diffuse region which may be narrow or wide. Furthermore, high surface densities and large silicate grains as well as iron and corundum grains decrease the rim radius, from a 2.2 AU radius for small silicates around a Herbig Ae star typically to 0.4 AU and as close as 0.2 AU. A passive disc with grain growth and a diverse dust composition must thus have a small inner rim radius. Finally, an analytical expression is presented for the rim location as a function of dust, disc and stellar properties.

Key words: stars: circumstellar matter -- stars: planetary systems: protoplanetary disks

© ESO 2009

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