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Guitar Nebula

March 16, 2013

Most of the stars in the Milky Way galaxy more or less go with the flow - they orbit the center of the galaxy in the same direction and at about the same speed as the stars around them.

But a few follow their own paths. An example is a star at the tip of the Guitar Nebula - a big bubble in space whose outline resembles a guitar. It’s in Cepheus, the king, which is low in the north on March evenings. The constellation’s brightest stars form an outline that resembles a child’s drawing of a house. Don’t look for the nebula, though, because it’s so faint that it wasn’t discovered until 1992.

It was sculpted by a pulsar - the crushed core of a once-mighty star. It spins once every two-thirds of a second, emitting a pulse of energy with each turn.

The pulsar was born when the star exploded as a supernova. The explosion must have been off-center, so it gave the dead core a powerful kick.

The pulsar is plowing through clouds of gas and dust at more than a million miles an hour. It leaves an expanding wake behind it, like a boat traveling across the ocean. That wake is what we see as the Guitar Nebula.

But there’s more to the nebula than what we can see. X-ray telescopes reveal a long, high-speed “jet” of material squirting away from the tip of the nebula. The jet most likely is powered by the pulsar’s magnetic field, which funnels material away from the pulsar - adding another interesting note to a celestial guitar.

More about pulsars tomorrow.


Script by Damond Benningfield, Copyright 2013

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