G299.2-2.9 is an intriguing supernova remnant found about 16,000 light years away in the Milky Way galaxy . Evidence points to G299.2-2.9 being the remains of a Type Ia supernova, where a white dwarf has grown sufficiently massive to cause a thermonuclear explosion. Because it is older than most supernova remnants caused by these explosions, at an age of about 4500 years, G299.2-2.9 provides astronomers with an excellent opportunity to study how these objects evolve over time. It also provides a probe of the Type Ia supernova explosion that produced this structure.
This composite image shows G299.2-2.9 in X-ray light from Chandra, along with data from the ROSAT satellite (orange), that has been overlaid on an infrared image from the Two Micron All-Sky Survey (2MASS). The faint X-ray emission from the inner region reveals relatively large amounts of iron and silicon, as expected for a remnant of a Type Ia supernova. The outer shell of the remnant is complex, with at least a double shell structure. Typically, such a complex outer shell is associated with a star that has exploded into space where gas and dust are not uniformly distributed.
-Megan Watzke, CXC