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Astron. Astrophys. 332, 849-856 (1998)


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The Chamaeleon infrared nebula revisited

Infrared imaging and spectroscopy of a young stellar object * **

Markus Feldt 1, Thomas Henning 1, Pierre O. Lagage 3, Volker Manske 1, Katharina Schreyer 1 and Bringfried Stecklum 2

1 Astrophysikalisches Institut und Universitäts-Sternwarte, Schillergäßchen 2-3, D-07745 Jena, Germany
2 Thüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg, Germany
3 Centre d' Etude de Saclay, F-91191 Gif-sur-Yvette Cedex, France

Received 23 September 1997 / Accepted 17 December 1997

Abstract

We are presenting spectroscopic and imaging data on the Chamaeleon Infrared Nebula (Cha IRN). Imaging was done between 1 and 2.5 µm and at 10 µm. Spectra of the object were obtained in the 2.1 µm - 4.6 µm range by ground-based measurements as well as using ISOPHOT-S in the 2.5 µm - 11.6 µm range. By combining these data with a K-band speckle image and IRAS-LRS data, we draw a complete picture of the source. The system's geometry, consisting of central source, disk, and bipolar outflow cavities, is determined directly from the observational data. Thereby we confirm earlier assumptions on the basic geometry of the system as well as support newer speculations by Gledhill et al. (1996) about the presence of a binary system inside the Cha IRN.

Additionally, we fit a radiative transfer model to the spectral energy distribution and derive the dust composition from the ISOPHOT spectra and give the resulting abundance ratios. The spectroscopic data point to an unusually silicate-poor environment of this young stellar object or a special geometric arrangement which leads to a suppression of the feature. They also indicate one of the most prominent H2 O ice features known as well as the presence of CO, CO2, and possibly NH3 ice.

Key words: stars: formation – ISM: jets and outflows – accretion, accretion disks – line: identification – radiative transfer

* Based on observations collected at the European Southern Observatory, La Silla, Chile
** based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) with the participation of ISAS and NASA

Send offprint requests to: M. Feldt (mfeldt@astro.uni-jena.de)

© European Southern Observatory (ESO) 1998

Online publication: March 30, 1998
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