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High-resolution imaging of ultracompact H II regions
II. G5.89-0.39 revisited *
M. Feldt 1,
B. Stecklum 2,
Th. Henning 1,
R. Launhardt 3 and
T.L. Hayward 4
Received 3 December 1998 / Accepted 3 February 1999
We present the results of an extensive imaging campaign on the ultracompact HII region G5.89-0.39 at near- and mid-infrared wavelengths. High-resolution data were taken in the H, , and L bands using ESO's adaptive optics system ADONIS. They are complemented by conventional narrow-band images in Br and as well as by mid-infrared broad- and narrow-band images. We also mapped the 1.3 mm continuum emission from the source using the SEST.
We use our data to consistently explain the morphological appearance of G5.89-0.39 at all observed wavelengths as well as its spectral energy distribution. The complete model of the source consists of a spherical shell of dust with an inner, dust-free cavity of 7.6 cm radius surrounding a star of spectral type O6 ZAMS. Two outflows escape this shell in opposite directions. Half of the whole configuration is evidently obscured by a very massive cloud of cold dust. Comparisons with earlier models and other ultracompact HII regions are drawn to put G5.89-0.39 in the context of massive star formation.
Key words: stars: formation stars: early-type ISM: H ii regions methods: observational
Send offprint requests to: M. Feldt (firstname.lastname@example.org)
Online publication: May 6, 1999