Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2001 October 28
See Explanation.  Clicking on the picture will download
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NGC 2346: A Butterfly-Shaped Planetary Nebula
Credit: Massimo Stiavelli (STScI), Inge Heyer (STScI) et al.,
& the Hubble Heritage Team (AURA/ STScI/ NASA)

Explanation: 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.

Tomorrow's picture: Black Hole Spin

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
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& Michigan Tech. U.