Infrared portrait of the nearby massive star-forming region IRAS 09002-4732

Abstract

We present high-resolution near-infrared and mid-infrared imaging, mid-infrared spectroscopy and millimetre- wavelength continuum observations of the nearby massive star-forming complex IRAS 09002-4732. A rich cluster of young stars displaying near-infrared excess emission is detected. We identify the ionising source of the ultracompact H II region G268.42-0.85 and show that this star is the dominant heating and illuminating source of the region. Spectral type estimates based on different methods are consistent with a star of spectral type O9. The combination of the new observations with litera- ture data allows us to set up the first structural model for the region. We argue that the ultracompact H II region is embedded in the rear side of the southern CS clump. Additionally, we detect several interesting objects. Among these objects are a network of dark dust filaments, an elongated, externally heated object with strong infrared excess inside the H II region and objects seen as silhouettes in the foreground of the large southern reflection nebulosity. The filamentary structures may play an important role in the star formation process.