Moon and Spica

StarDate: June 8, 2014

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The Moon stages its second close encounter in as many nights tonight — this one with Spica, the brightest star of Virgo. Spica’s close to the right of the Moon as night falls, and remains close as they drop down the sky later on.

Spica actually consists of two stars. One of them, known as Spica A, is more than 10 times as massive as the Sun — so heavy that it’ll probably end its life with a titanic explosion known as a supernova.

But Spica’s other star is no slouch, either. Known as Spica B, it’s about six or seven times as massive as the Sun, and perhaps 1500 times brighter. That easily makes it a one percenter — it puts it in the top one percent of the galaxy’s biggest and brightest stars.

Spica B’s fate won’t be quite as impressive as that of its companion, though. It’s below the weight limit that tips a star into the supernova category. Instead, its fate is probably much like the Sun’s.

As the star ages — a process that’s much faster in heavy stars than in lighter ones, like the Sun — it’ll puff up to many times its current size. Then it’ll blow its outer layers into space, leaving only its hot, dense core — a white dwarf. This white dwarf will be among the galaxy’s biggest.

Of course, that scenario depends on what happens with Spica A. The two stars are quite close together, so interactions between them could alter the fate of either or both — making predictions of their future a bit iffy.

 

Script by Damond Benningfield, Copyright 2014

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