Large-scale structure of the Carina Nebula

Observations obtained with the Midcourse Space Experiment (MSX) satellite r eveal for the first time the complex mid-infrared morphology of the entire Carina Nebula (NGC 3372). On the largest size scale of similar to 100 pc, t he thermal infrared emission from the giant H II region delineates one cohe rent structure: a (somewhat distorted) bipolar nebula with the major axis p erpendicular to the Galactic plane. The Carina Nebula is usually described as an evolved H II region that is no longer actively forming stars, clearin g away the last vestiges of its natal molecular cloud. However, the MSX obs ervations presented here reveal numerous embedded infrared sources that are good candidates for sites of current star formation. Several compact infra red sources are located at the heads of dust pillars or in dark globules be hind ionization fronts. Because their morphology suggests a strong interact ion with the peculiar collection of massive stars in the nebula, we specula te that these new infrared sources may be sites of triggered star formation in NGC 3372.