| Issue |
A&A
Volume 483, Number 1, May III 2008
|
|
|---|---|---|
| Page(s) | L9 - L12 | |
| Section | Letters | |
| DOI | https://doi.org/10.1051/0004-6361:200809697 | |
| Published online | 01 April 2008 | |
Letter to the Editor
Is the silicate emission feature only influenced by grain size?*
1
Sobolev Astronomical Institute, St. Petersburg University, Universitetskii prosp. 28, St. Petersburg 198504, Russia e-mail: nvv@astro.spbu.ru
2
Isaac Newton Institute of Chile, St. Petersburg Branch, Russia
3
Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
Received:
3
March
2008
Accepted:
21
March
2008
The flattening of the 10 
silicate emission feature
observed in the spectra of T Tauri and Herbig Ae/Be stars
is usually interpreted as an indicator of grain growth.
We show in this paper that a similar behaviour of the feature shape occurs
when the porosity of composite grains varies.
We modelled the fluffy aggregates with inclusions of different sizes with
multi-layered spheres consisting of
amorphous carbon, amorphous silicate, and vacuum.
We also found that
the inclusion of crystalline silicates in composite porous particles
can lead to a shift of the known resonances and production of new ones.
Key words: line: profiles / stars: pre-main-sequence / stars: planetary systems: protoplanetary disks / stars: circumstellar matter / infrared: stars / ISM: dust, extinction
© ESO, 2008
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