Astron. Astrophys. 364, 613-624 (2000)

IRAS 12326-6245: Luminous very young stellar objects with a massive molecular outflow ^*

Th. Henning ¹, A. Lapinov ², K. Schreyer ¹, B. Stecklum ⁴ and I. Zinchenko <sup>2,3

1</sup> Friedrich Schiller University Jena, Astrophysical Institute and University Observatory (AIU), Schillergässchen 2-3, 07745 Jena, Germany
² Institute of Applied Physics of the Russian Academy of Sciences, 46 Uljanov str., 603600 Nizhny Novgorod, Russia
³ Helsinki University Observatory, Tähtitorninmäki, P.O. Box 14, 00014 University of Helsinki, Finland
⁴ Thuringian State Observatory, Sternwarte 5, 07778 Tautenburg, Germany

Received 20 March 2000 / Accepted 19 October 2000

Abstract

We present a comprehensive study of the luminous young stellar object IRAS 12326-6245 at near- and mid-infrared wavelengths as well as in the millimetre wavelength range.

IRAS 12326-6245 is associated with two ultracompact H II regions. These massive young stellar objects are surrounded by a cluster of stars revealed by the near-infrared images. With N- and Q-band imaging, we find four very deeply embedded mid-infrared sources which form a remarkable proto-Trapezium system. Both ultracompact H II regions are associated with mid-infrared sources. In addition, a -band nebulosity is present which outlines the rim of the molecular outflow.

The mapping in different molecular lines as well as in the 1.3 mm continuum shows that IRAS 12326-6245 is deeply embedded in a dense molecular cloud core in agreement with the steeply rising infrared spectral energy distributions of the ultracompact H II regions. In the region one of the most energetic and massive bipolar molecular outflows was detected in CO(2-1), C¹⁸O(2-1), and SO with its origin close to IRAS 12326-6245.

Key words: stars: formation ISM: clouds ISM: individual objects: IRAS 12326-6245 ISM: molecules radio lines: ISM

* Based on observations collected at the European Southern Observatory, La Silla, Chile

Send offprint requests to: Th. Henning

Correspondence to: henning@astro.uni-jena.de

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observations
  • 2.1. Molecular observations
  • 2.2. Bolometer observations
  • 2.3. Imaging in H, J, and H₂
  • 2.4. N- and Q-band imaging
• 3. Results
  • 3.1. Infrared data
  • 3.2. Structure of the region at millimetre wavelengths
  • 3.3. Outflow
• 4. Discussion
  • 4.1. General properties
  • 4.2. Physical parameters of the core and envelope
  • 4.3. Outflow
• 5. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: January 29, 2001
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