Death is a topic that inspires dread and fear in most people. When it comes to stars, however, we positively marvel at it. The colors, patterns and gargantuan displays of shimmering cosmic dust are universally accepted to be nothing less than beautiful. Hubble has once again shown us that the universe is a constantly changing, violent place to be: the remnants of a star’s explosive death, apparently frozen in time, have been photographed and beamed back to our pale, blue dot. Located in the constellation of Norma, PK 329-02.2, known more memorably as Menzel 2, is a planetary nebula named after the astronomer Donald Menzel, who first laid eyes on the stellar remains way back in 1922.
Planetary nebulae are, misleadingly, nothing to do with planets; they are the final consequence of a star’s death. If a star is equivalent to a mass of eight of our own Suns or more, then it will likely reach the end of its life with a supernova explosion, which always briefly outshine the light of an entire galaxy.
Planetary nebulae, which are formed during the prolonged deaths of stars with a much lower mass, are far more graceful affairs. When the star can no longer burn its fuel through the nuclear fusion of hydrogen, the immense gravitational field around the star begins to compress its core. This increases the temperature of most star cores 10-fold, blasting out the outer, cooler layers of the star into deep space. This exposes the searing core of the star, which blasts out ultraviolet radiation, energetically exciting the ejected outer shell, causing it to appear to shine.
So what you’re seeing here in this striking Hubble image is just that: the death throes of a star, which astronomers think is the brighter of the two stars at the center of the image.
This immense cloud of stellar dust, rich in heavier elements including carbon, nitrogen and oxygen, will one day in the very distant future be part of another star system, or even a planet, very different or perhaps very similar to our own.
Image credit: NASA