Spirograph Eye

Credit: NASA and The Hub­ble Her­itage Team (STScI/AURA)

Glow­ing with many col­ors, the plan­e­tary neb­ula called the Spiro­graph Neb­ula, shows the last stage of a star’s life. After run­ning out of hydro­gen fuel, the star at the cen­ter grew to a huge red giant. Then the star shed its outer lay­ers, cre­at­ing a bub­ble in space. Even­tu­ally the small hot core left behind will become a white dwarf.

The pat­terns inside this neb­ula are not under­stood. Astronomers, using this image from NASA’s Hub­ble Space Tele­scope, think that per­haps the star is chang­ing rapidly. Stars at this age become brighter and dim­mer quickly. The star’s solar wind also changes rapidly and unpre­dictably. These winds blow the gas and dust in var­i­ous direc­tions away from the star.

Just a few mil­lion years ago, the star at the cen­ter of the neb­ula, IC 418, was much like the sun. Our Sun will go through a sim­i­lar process but not for another five bil­lion years. For now the hot core of the red giant is all that is left behind. The ultra­vi­o­let radi­a­tion com­ing from this star is intense and causes the bub­ble to glow, blue for hot gas and red for the cooler outer lay­ers. The neb­ula from side to side is about two-tenths of a light year across; that’s 13,000 times the dis­tance from the Earth to the Sun!

IC 418 lies about 2,000 light-years from Earth toward the con­stel­la­tion Lepus, the hare or rab­bit. Lepus is found near the con­stel­la­tion of Orion.