EDP Sciences
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Volume 417, Number 3, April III 2004
Page(s) 981 - 985
Section Interstellar and circumstellar matter
DOI http://dx.doi.org/10.1051/0004-6361:20035631

A&A 417, 981-985 (2004)
DOI: 10.1051/0004-6361:20035631

Peering into the heart of a high-mass star forming region: Bispectrum speckle interferometry of the ultracompact H II region K3-50 A

K.-H. Hofmann1, Y. Y. Balega2, T. Preibisch1 and G. Weigelt1

1  Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
2  Special Astrophysical Observatory, Nizhnij Arkhyz, Zelenchuk region, Karachai-Cherkesia 357147, Russia

(Received 5 November 2003 / Accepted 24 December 2003 )

We present K'-band bispectrum speckle interferometry of the ultracompact H II region K3-50A. Our image resolves the central $1''\times 1''$ region into at least 7 point-like objects. We find K'-band counterparts for all but one of the N-band sources discovered by Okamoto et al. (2003), and there are additional K'-band sources which were unresolved in the N-band images. Our reconstructed image also reveals the fine-structure of the cone-shaped nebulosity extending to the south. The brightest K'-band source is located exactly at the tip of the cone-shaped nebulosity. The nebula shows several arcs and the orientation of its main axis agrees very well with the direction of the CO outflow from K3-50A. This nebulosity therefore very likely represents the clumpy inner surface of a partially evacuated cavity excavated by the strong outflows.

Key words: techniques: interferometric -- stars: formation -- stars: pre-main sequence -- H II regions: individual: G70.293+1.600

Offprint request: T. Preibisch, preib@mpifr-bonn.mpg.de

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