A SECRET STAR AT THE CENTRE OF THE CAT’S EYE NEBULA
WORDS BRANDON SPECKTOR
When a star roughly the size of the Sun approaches the end of its life, it expels its outer layers of gas into a bright, beautiful bubble known as a planetary nebula. At the centre of each bubble, a weakened star irradiates its surroundings, sculpting the gas. One of the strangest of these cosmic clouds is the Cat’s Eye Nebula, located about 3,000 light years from Earth. Seemingly made of several overlapping bubbles of blue gas with long, streamer-like filaments wrapped tightly around them, the nebula has defied clear explanation for centuries.
Using data from the San Pedro Mártir National Observatory in Mexico showing the movements of layers of gas in the nebula, astronomers created the first-ever 3D model of the Cat’s Eye Nebula. Their map reveals a pair of perfectly symmetrical rings swirling around the entire length of the nebula’s outer shell. According to the researchers, there’s only one possible cause of these rings’ symmetry: a double-barrelled burst of energy known as a precessing jet. As the nebula’s central star died, it released twin bursts of high-density gas in opposite directions at the same time. But rather than remaining fixed in place, the jets began to wobble like a spinning top, leaving slowly looping rings of gas twirling above and below the star.