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July 9, 2013

Several of the biggest, heaviest stars in the galaxy dot the sky tonight. As night falls, Deneb, which forms the tail of Cygnus, the swan, is in the east-northeast. Antares, the orange heart of Scorpius, is about the same height in the south. And Spica, the leading light of Virgo, is a little higher in the southwest.

The main stars in these systems are each at least 10 times as massive as the Sun, and Antares may be close to 20 times the Sun’s mass.

Yet even these giants may be pipsqueaks compared to a pair of stars in a nearby galaxy. The stars form a binary system known as R144. It’s in a huge cluster of hot, young stars in the Large Magellanic Cloud, a nearby companion galaxy to the Milky Way.

A team of European astronomers used the Very Large Telescope in Chile to break the star’s light into its individual wavelengths or colors. That showed that the system consists of two stars that are orbiting each other. It also showed that both stars are members of an extremely hot and heavy class of stars.

The astronomers also found that the two stars are roughly the same mass. The big surprise is that their combined mass is roughly 200 to 300 times the mass of the Sun. What’s more, based on models of how such stars evolve, the system must have been roughly a hundred solar masses heavier when the stars were born.

If the finding is confirmed, it would make the stars of R144 the heaviest yet discovered — the “megastars” of the stellar family.


Script by Damond Benningfield, Copyright 2013

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