As stars like our own Sun die, they do so with beautiful complexity. First, they exhaust the hydrogen in their cores, having fused it into helium. As the star contracts, the core gets hotter until helium begins fusing into carbon, nitrogen, and oxygen. The resulting heat and pressure causes the outer envelope to expand, and eventually dissipate out into the cosmos. The result, is a planetary nebula like the one you see here.
At the center of the nebula lies the relic of what used to be the star’s core, known as a White Dwarf. What’s particularly interesting about this white dwarf is that it pulsates over time.[1. This pulsation shouldn’t be confused with a pulsar, which is a far denser object and a very different animal.] In NGC 2452’s case, the white dwarf seems to undergo occasional gravitational wave disturbances that propagate across the surface, like a ripple in a pond traversing the entire surface of the star.
NGC 2542 appears almost ghost-like in this Hubble Space Telescope image, which is perfect since we’re nearing Halloween. It’s blue-like appearance is the result of the optical (colored cyan) and infrared (colored red) filters used to make this image. It’s eerie and awesome at the same time.