jueves, 13 de septiembre de 2007

Coronet: A Star Formation Neighbor

While perhaps not quite as well known as its star formation cousin of Orion, the Corona Australis region (containing, at its heart, the Coronet Cluster) is one of the nearest and most active regions of ongoing star formation. At only about 420 light years away, the Coronet is over three times closer than the Orion Nebula is to Earth. The Coronet contains a loose cluster of a few dozen young stars with a wide range of masses and at various stages of evolution, giving astronomers an opportunity to observe "protostars" simultaneously in several wavelengths.

This composite image shows the Coronet in X-rays from Chandra (purple) and infrared emission from Spitzer (orange, green, and cyan). The Spitzer image shows young stars plus diffuse emission from dust. In the Chandra data only (see inset), many of these young stars appear as blue objects, revealing their output of high-energy X-rays and the amount of obscuring dust and gas in the region. The reason for the blue appearance is that lower energy X-rays, which are depicted as red and green, are absorbed by this veil of material and hence are not seen. The Chandra data also support the idea that X-rays from very young stars are generated largely from magnetic activity in the outer atmospheres. Due to the host of young stars in different life stages in the Coronet, astronomers can use these data to pinpoint details of how the youngest stars evolve.

Image credit: X-ray: NASA/CXC/CfA/J. Forbrich; Infrared: NASA/Spitzer/CfA/L. Allen