Abstract
VLT-ISAAC K band imaging of G284.0-0.8 (IRAS 10184-5748), which we discovered during our extensive CS (2-1) survey of 1600 ultra-compact HII regions (Bronfman et al. 1996, A&AS 115,81), reveals G284 as a promising region with which to study mass segregation in the birth sites of massive stars.
G284.0-0.8 is a very small ultra-compact HII, of irregular shape in the classification scheme of Wood & Churchwell (1989, ApJS, 69, 831), and probably belongs to the carina arm witch has a minimum distance of 4.11(Grabelsky 1988, ApJ, 331, 181). Its Ks image shows two clusters of ionizing stars embedded in extended emission, but the Js and H counterparts are weak. Seven ionizing stars are clustered within the ultra-compact HII region, which is itself surrounded by many faint stars lacking circumstellar nebulosity and J detections. Here we present Js, H, Ks, M and M imaging and photometry of G284.0-0.8.