Vela

StarDate: April 4, 2013

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The constellation Vela represents the sail of the Argo, the ship that carried Jason and the Argonauts. It’s quite low in the south as darkness falls this evening. Only one of its stars is much to look at. But if our eyes were more sensitive, we’d see that Vela is home to one of the largest individual objects in Earth’s night sky - the remains of an exploded star.

The Vela Supernova Remnant was born about 12,000 years ago as seen from Earth when a giant star exploded. The blast sent the star’s outer layers racing into space at a few percent of the speed of light.

This cloud of material continues to expand, so today it’s dozens of light-years across. At a distance of about 800 light-years, that makes it about as big as your fist held at arm’s length.

As the debris rams into surrounding clouds of gas and dust, it heats them and causes them to glow, creating a tenuous but beautiful nebula. The nebula contains a diverse brew of chemical elements created in the heart of the star, or in the supernova blast itself.

Not all of the star was destroyed, though. Its core was crushed to form a neutron star - an object that’s more than twice as heavy as the Sun, but only as wide as a mid-sized American city. The neutron star spins 11 times per second. With each turn, a beam of radio energy sweeps across Earth, so the star “pulses” on and off - a pulsating beacon for the ancient Argo.

More about Vela tomorrow.

 

Script by Damond Benningfield, Copyright 2013

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