The interplay of the stars in a binary system can produce some amazing sights. One example is NGC 2346, a colorful cloud of gas and dust. It’s about 4800 light-years away, in the unicorn. It looks a bit like a butterfly with its wings unfurled.

The nebula is the final gasp of a dying star. The star could no longer sustain the nuclear reactions in its core, so the core shut down. The star’s outer layers were expelled into space, forming a giant, bright cloud.

Many nebulas of this type form bubbles — still beautiful, but much simpler. Many of those nebulas were produced by single stars. But NGC 2346 was sculpted by two stars — the dying star and a companion.

As the first star began to die, it expanded to giant proportions. It engulfed its companion. But the companion survived.  Its motion stripped away material from the expanding star’s outer layers, forming a ring around the equator.

As the expanding star died, radiation from its hot core pushed away the gas in its outer layers. The gas was hemmed in by the ring around the equator, though, so it spread out from the poles. That formed two bubbles — one from each pole. Today, the bubbles form the “wings” of this beautiful cosmic butterfly.

NGC 2346 is in Monoceros, the unicorn. The nebula is close to the upper right of the bright star Procyon, which is low in the southeast at nightfall. The butterfly is an easy target for small telescopes.
 

Script by Damond Benningfield

Support McDonald Observatory