Issue |
A&A
Volume 485, Number 2, July II 2008
|
|
---|---|---|
Page(s) | 531 - 540 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20065685 | |
Published online | 28 April 2008 |
Multiwavelength studies of the gas and dust disc of IRAS 04158+2805*
1
Paul Scherrer Institut, 5232 Villigen PSI, Switzerland e-mail: glauser@phys.ethz.ch;adrian.glauser@psi.ch
2
Laboratoire d'Astrophysique de Grenoble, CNRS/UJF UMR 5571, BP 53, 38041 Grenoble Cedex 9, France
3
School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
4
Astronomy Department, UC Berkeley, Berkeley CA 947209-3411, USA
5
Caltech-JPL/IPAC, Mail Code 100-22, Pasadena, CA 91125, USA
Received:
24
May
2006
Accepted:
14
April
2008
We present a study of the circumstellar environment of
IRAS 04158+2805 based on multi-wavelength observations and
models. Images in the optical and near-infrared, a polarisation map
in the optical, and mid-infrared spectra were obtained with
VLT-FORS1, CFHT-IR, and Spitzer-IRS. Additionally we used an
X-ray spectrum observed with Chandra. We interpret the observations
in terms of a central star surrounded by an axisymmetric
circumstellar disc, but without an envelope, to test the validity of
this simple geometry. We estimate the structural properties of the
disc and its gas and dust content. We modelled the dust disc with a
3D continuum radiative transfer code, MCFOST, based on a Monte-Carlo
method that provides synthetic scattered light images and
polarisation maps, as well as spectral energy distributions. We find
that the disc images and spectral energy distribution narrowly
constrain many of the disc model parameters, such as a total dust
mass of 1.0-1.7510-4
and an inclination of
62°-63°. The maximum grain size required to fit all
available data is of the order of 1.6-2.8 μm although the
upper end of this range is loosely constrained. The observed optical
polarisation map is reproduced well by the same disc model,
suggesting that the geometry we find is adequate and the optical
properties are representative of the visible dust content. We
compare the inferred dust column density to the gas column density
derived from the X-ray spectrum and find a gas-to-dust ratio along
the line of sight that is consistent with the ISM value. To our
knowledge, this measurement is the first to directly compare dust
and gas column densities in a protoplanetary disc.
Key words: stars: circumstellar matter / stars: pre-main-sequence / stars: individual: IRAS 04158+2805 / stars: formation / stars: planetary systems: protoplanetary discs
Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. Based also on data collected at ESO/VLT during observation program 68-C.0171.
© ESO, 2008
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