Tour: When a Stable Star Explodes

White dwarfs are among the most stable of stars. They are stars that have exhausted most of their nuclear fuel and shrunk to about the size of Earth, yet still contain about the same mass as the Sun. Left on their own, white dwarfs can last for billions or even trillions of years. However, a white dwarf with a nearby companion star can become a cosmic powder keg. If the companion’s orbit brings it too close, the white dwarf can pull material from it until the white dwarf grows so much that it becomes unstable and explodes. This kind of stellar blast is called a Type Ia supernova. While astronomers generally accept that such encounters between white dwarfs and “normal“ companion stars are one likely source of Type Ia supernova explosions, many details of the process are not well understood. One way to investigate the explosion mechanism is to look at the elements left behind by the supernova in its debris or ejecta. Chandra is one of the best tools available for scientists to study supernova remnants and me