1. Stellar Evolution with Type 1a Supernova Remnant
This graphic gives a summary of our best current understanding of the evolution of stars, showing their birth, middle age and eventual demise. The lowest mass stars are shown at the bottom and the highest mass stars at the top. The very top line is a relatively recent addition compelled by the detection of SN 2006gy, that describes the evolution of the most massive stars in the universe. Observational evidence for the special type of explosion shown here - which is incredibly bright and obliterates the star rather than producing a black hole - was lacking until SN 2006gy was found. (illustration: NASA/CXC/M.Weiss)
Field Guide: Stellar Evolution

2. Stellar Evolution
This tableau illustrates the ongoing drama of stellar evolution, and how the rate of evolution and the ultimate fate of a star depends on its weight, or mass. (Illustration: NASA/CXC/M.Weiss)
Field Guide: Stellar Evolution

3. Charge-Exchange
Charge-exchange is an atomic collision process in which a charged ion, for example, a carbon or oxygen ion, collides with a neutral atom or molecule and captures one of its electrons. A photon is emitted as the captured electron drops to a lower energy state. (Illustration: NASA/CXC/M.Weiss)