EDP Sciences
Free access
Issue
A&A
Volume 422, Number 2, August I 2004
Page(s) 621 - 626
Section Interstellar and circumstellar matter
DOI http://dx.doi.org/10.1051/0004-6361:20040197


A&A 422, 621-626 (2004)
DOI: 10.1051/0004-6361:20040197

Correlation between grain growth and disk geometry in Herbig Ae/Be systems

B. Acke1, M. E. van den Ancker2, C. P. Dullemond3, R. van Boekel4 and L. B. F. M. Waters1, 4

1  Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200B, 3001 Leuven, Belgium
    e-mail: bram.acke@ster.kuleuven.ac.be
2  European Southern Observatory, Karl-Schwarzschild Strasse 2, 85748 Garching bei München, Germany
3  Max-Planck-Institut für Astrophysik, Karl-Schwarzschildstrasse 1, Postfach 1317, 85748 Garching bei München, Germany
4  Astronomical Institute "Anton Pannekoek", University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands

(Received 4 February 2004 / Accepted 24 April 2004)

Abstract
We have calculated the (sub-)mm spectral indices of 26 Herbig Ae/Be stars, for which we can determine the infrared spectral energy distribution (SED). We find a clear correlation between the strength of the ratio of the near- to mid-infrared excess of these sources, and the slope of the (sub-)mm energy distribution. Based on earlier multi-dimensional modeling of disks around Herbig Ae stars, we interpret this as a correlation between the geometry of the disk (flared or self-shadowed) and the size of the grains: self-shadowed disks have, on average, larger grains than their flared counterparts. These data suggest that the geometry of a young stellar disk evolves from flared to self-shadowed.


Key words: stars: circumstellar matter -- stars: planetary systems: protoplanetary disks -- stars: pre-main-sequence

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© ESO 2004