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Delta Scorpii

August 8, 2016

Mars is butting heads with the scorpion. The bright planet is just a whisker away from Delta Scorpii, the star in the middle of the head of Scorpius.

Delta Scorpii is an intriguing system. Its main star is only about 10 million years old — a mere infant on the stellar timescale. Yet it’s also about 13 times as massive as the Sun. Such heavy stars “burn” their nuclear fuel in a hurry, so they age much faster than smaller stars. So Delta Scorpii’s main star is already nearing the end of its normal lifetime.

The star is spinning rapidly, so it’s throwing off a lot of hot gas, which cools and condenses to make tiny grains of dust. These grains form a disk that’s at least 125 million miles wide.

The star and a companion follow an elongated orbit around each other. At their closest, they almost touch. That appears to cause the system to flare brightly. In fact, during the two most recent encounters, Delta Scorpii jumped to almost twice its normal brightness.

Over the next few million years, the main star will puff up to enormous proportions, so it’ll shine many times brighter still. After that, it’s likely to explode as a supernova — briefly giving the scorpion a big head.

Mars and Delta Scorpii are in the south as night falls. Mars looks like a brilliant orange star. Delta Scorpii is quite close above Mars. The scorpion’s bright orange heart, the star Antares, is to their lower left, with the rest of Scorpius curving down near the horizon.


Script by Damond Benningfield

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