RCW 49 (also designated GUM 29) is a diffuse nebula of about 350 light-years across, located 13,700 light years away in the southern constellation Centaurus. It is a dark and dusty stellar nursery that contains more than 2,200 stars.
Because many of the stars in RCW 49 are deeply embedded in plumes of dust, they cannot be seen at visible wavelengths. When viewed with Spitzer’s infrared eyes, however, RCW 49 becomes transparent.
This image highlights the nebula’s older stars (blue stars in center), its gas filaments (green) and dusty tendrils (pink). But it also uncovers more than 300 newborn stars, speckled throughout the cosmic dust clouds what shows that star formation is taking place throughout the nebula. Astronomers are interested in further studying these newfound proto-stars because they offer a fresh look at star formation in our galaxy.
RCW 49 is one of the most luminous and massive H II regions (a low-density cloud of partially ionized gas in which star formation has recently taken place) in our Milky Way galaxy. At its center lies the Westerlund 2 compact star cluster, which contains some of the hottest, brightest, and most massive stars known. The age of the W2 cluster is estimated to be 23 million years. The estimated stellar mass of the cluster is about 30,000 solar masses.
The infrared data indicate the likely presence of protoplanetary disks around some of the infant stars, among the faintest and farthest potential planet-forming disks ever observed. Such exciting results give further support to the idea that planet-forming disks are a natural part of a star’s evolution.
This image is taken with the infrared array camera on NASA’s Spitzer Space Telescope.
Image Credit: E. Churchwell (University of Wisconsin), NASA/JPL-Caltech