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Butterfly Nebula

August 6, 2016

The scorpion is one of the most unappealing creatures on the planet. The celestial scorpion, however, offers one of the most appealing creatures in the galaxy: the Butterfly Nebula. This amazing structure emerged from its cocoon about 2,000 years ago as seen from Earth. Today, its colorful wings spread across more than two light-years.

The “wings” are big bubbles of gas and dust. They once formed the outer layers of a star that was heavier than the Sun. The star’s hot but dead core sits at the center of the nebula.

Until the last couple of thousand years, the core generated energy through nuclear fusion. Today, though, that process has stopped. The leftover core, which is about two-thirds as massive as the Sun, shines perhaps 2,000 times brighter than the Sun. And its surface is hundreds of thousands of degrees hotter than the Sun’s.

But the dying core may be fading by as much as one percent per year. And it will continue to cool and fade rapidly over the next few millennia. At the end of that time, the core will be a white dwarf — a dense ball not much bigger than Earth. By then, the surrounding butterfly will begin to fade, destroying a bit of beauty in the celestial scorpion.

And look for the scorpion low in the south as night falls, with the bright planets Mars and Saturn close by. The Butterfly Nebula is near the stars that mark the stinger, although you need a telescope to see it.

Tomorrow: A bright companion for the Moon

Script by Damond Benningfield

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