EDP Sciences
Free access
Volume 412, Number 3, December IV 2003
Page(s) 751 - 765
Section Formation, structure and evolution of stars
DOI http://dx.doi.org/10.1051/0004-6361:20031406

A&A 412, 751-765 (2003)
DOI: 10.1051/0004-6361:20031406

The Trumpler 14 photodissociation region in the Carina Nebula

K. J. Brooks1, 2, P. Cox3, N. Schneider4, J. W. V. Storey5, A. Poglitsch6, N. Geis6 and L. Bronfman1

1  Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
2  European Southern Observatory, Casilla 19001 Santiago, Chile
3  Institut d'Astrophysique Spatiale, Université de Paris-Sud, 91405 Orsay Cedex, France
4  Observatoire de Bordeaux, Université de Bordeaux I, 33270 Floirac Cedex, France
5  School of Physics, University of New South Wales, Sydney 2052, NSW, Australia
6  Max Planck für Extraterrestrische Physik, Garching bei München, Germany

(Received 23 June 2003 / Accepted 9 September 2003)

We report the results of observations of the fine-structure emission lines [ $\ion{C}{ii}$] 158  $\rm\mu m$ and [ $\ion{O}{i}$] 63  $\rm\mu m$ using FIFI on the Kuiper Airborne Observatory (KAO) and the Long Wavelength Spectrometer (LWS) on board ISO, towards the molecular cloud associated with the stellar cluster Trumpler 14 (Tr 14) in the Carina Nebula. These data are compared with selected CO and CS transitions obtained with the SEST as well as IRAS and MSX images to produce a detailed view of the morphology and the physical conditions prevailing in the photodissociation region (PDR) at the interface between the ionized gas and the molecular dust lane. The relative intensity distribution observed for the various tracers is consistent with the stratification expected for a molecular cloud seen edge-on and exposed to a radiation field of  $\approx$ $ \rm 10^4 \, G_0$, which is dominated by the most massive stars of Tr 14. The grain photoelectric heating efficiency, $\epsilon$, is estimated to be $\approx$ $5 \times 10^{-3}$ and is comparable to other galactic PDRs. The molecular gas has a complicated velocity structure with a high velocity dispersion resulting from the impact of the stellar winds arising from Tr 14. There is evidence of small-scale clumping with a very low volume filling factor. Despite the rich concentration of massive O stars in Tr 14 we find that the parameters of the PDR are much less-extreme than those of the Orion and M 17 massive star-forming regions.

Key words: stars: formation -- ISM: lines and bands -- ISM: clouds -- ISM: individual objects: Carina nebula

Offprint request: K. J. Brooks, kbrooks@das.uchile.cl

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