The origin of crystalline silicates in the Herbig Be star HD100546 and in comet Hale-Bopp

Astrophysics, abstract
astro-ph/0301254

From: Jeroen Bouwman <bjeroen@cea.fr>

Date: Tue, 14 Jan 2003 13:47:31 GMT   (240kb)

Authors:
J. Bouwman (1 and 2),
A. de Koter (1),
C. Dominik (1),
L.B.F.M Waters (1 and 3) ((1) Astronomical Institute “Anton Pannekoek”, University of Amsterdam, The Netherlands, (2) CEA/DSM/DAPNIA, Service d’Astrophysique, France, (3) Instituut voor Sterrenkunde, K.U. Leuven, Belgium)

Comments: 17 pages, 10 figures, Accepted for publication in Astronomy and
Astrophysics

We have investigated the spatial distribution, and the properties and
chemical composition of the dust orbiting HD 100546. This system is remarkably
different from other isolated Herbig Ae/Be stars in both the strength of the
mid-IR excess and the composition of the circumstellar dust. We speculate that
the formation and spatial distribution of the crystalline dust observed in the
HD 100546 system may be linked to the formation of a proto-Jupiter in the disk
around HD 100546. Such a proto-Jupiter could gravitationally stir the disk
leading to a collisional cascade of asteroidal sized objects producing small
crystalline grains, or it could cause shocks by tidal interaction with the disk
which might produce crystalline dust grains through flash heating. As shown by
Malfait et al. (1998), the infrared spectrum of HD 100546 is very similar to
that of C/1995 O1 Hale-Bopp (Crovisier et al. 1997). Using an identical
methodology, we have therefore also studied this solar system comet. Both
objects have an almost identical grain composition, but with the important
difference that the individual dust species in Hale-Bopp are in thermal contact
with each other, while this is not the case in HD 100546. This suggests that if
similar processes leading to the dust composition as seen in HD 100546 also
occurred in our own solar system, that Hale-Bopp formed after the formation of
one or more proto-gas giants.

References and citations for this submission:

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