NGC 2346: A Butterfly-Shaped Planetary Nebula
It may look like a butterfly, but it's bigger than our
Solar System.
NGC 2346 is a
planetary nebula made of gas and
dust
that has evolved into a
familiar shape.
At the heart of the
bipolar planetary nebula
is a pair of close stars orbiting each other
once every sixteen days.
The tale of how the butterfly blossomed probably
began millions of years ago, when the stars were farther apart.
The more massive star expanded to encompass its
binary companion,
causing the two to spiral closer and expel
rings of gas.
Later, bubbles of hot gas emerged as the core of the massive
red giant star became uncovered.
In billions of years, our Sun will become a
red giant and emit a
planetary nebula - but probably not in the shape of a
butterfly, because the
Sun has no binary star companion.