Holiday bauble made by supernova

This delicate shell, photographed by the Hubble Space Telescope, appears to float serenely in the depths of space, but this apparent calm hides an inner turmoil. The gaseous envelope formed as the expanding blast wave and ejected material from a supernova tore through the nearby interstellar medium.

The Hubble Space Telescope has gifted us this festive-looking image of a bauble of gas serenely floating in the Large Magellanic Cloud, a Milky Way satellite galaxy that’s about 160,000 light years from Earth.

This is no mere Christmas ornament, though. The delicate shell of gas hides the violent turmoil behind its creation: The envelope formed as the expanding blast wave and ejected material from the explosion of a dying star tore through the nearby interstellar medium.

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According astronomers with the Space Telescope Science Institute, the explosion was a particularly violent supernova known as a Type Ia, which results when a white dwarf star in a binary system robs its partner of material. Once the greedy white dwarf finally takes on more mass than it can handle, it violently explodes.

The ripples in the shell’s surface may be caused either by subtle variations in the density of the surrounding interstellar gas — or are perhaps driven from within the bauble by fragments from the initial explosion. The ornament-like bubble, called SNR B0509-67.5, is 23 light-years across and expanding at more than 11 million miles (18 million kilometers) an hour, according the analysis team.

Astronomers say the supernova occurred about 400 years ago and might have been visible to Southern Hemisphere observers around the year 1600, though there are no records of a “new star” — as supernova were erroneously called — in the direction of the Large Megallanic Cloud near that time.

Hubble’s Advanced Camera for Surveys observed the supernova remnant on Oct. 28, 2006, with a filter that isolates light from the glowing hydrogen seen in the expanding shell. To make the image shown here, these observations were combined with visible-light images of the surrounding star field that were imaged by Hubble’s Wide Field Camera 3 on Nov. 4 of this year.

More information on supernovae:

* Physicists replicate a supernova in laboratory * Supernova blast wave could shape galaxy evolution * Scientists identify brightest supernova * Star death may explain universe’s biggest bangs * New type of supernova discovered * Supernova nightmares * New risk to Earth from supernova explosions

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John Roach is a contributing writer for Connect with the Cosmic Log community by hitting the “like” button on the Cosmic Log Facebook page or following’s science editor, Alan Boyle, on Twitter (@b0yle).


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