Chandra Release - October 14, 2003

Visual Description: Crescent Nebula

A colorful composite X-ray and optical image of the Crescent Nebula (NGC 6888) is displayed. The image features bright blue and green hues, with a wispy red curving around it. The main structure of the nebula appears to be shaped like a crescent moon, hence its name, and populated with bright sources. The Crescent Nebula is a giant gaseous shell created by powerful winds blowing from a massive star called HD 192163.  The collision of winds compressed gas into a dense shell (red), and produced two shock waves: an outward-moving shock that is visible at optical wavelengths (green), and an inward-moving shock wave that created a bubble of two million degree X-ray emitting gas (blue). HD 192163 will likely explode as a supernova in about a hundred thousand years.  Because massive stars explode as supernovas, knowledge of the environment around this star will help astronomers better understand supernovas and their remnants.