Massive Stars Colliding!

News always reports the records.  The biggest, the loudest, the fastest, the first.  When it comes to Astronomy, there are so many new worlds to explore and so much new science to learn, we end up breaking records often.  Even with Astronomy being the oldest science, the sheer amount of stuff in the universe means there is always something new and surprising to discover. Today’s episode of ‘Biggest, brightest, hottest’ brings us the move massive binary star system ever found, with two huge, hot stars so close together that they are actually touching, merging their atmospheres together.

This artist’s impression shows VFTS 352 — the hottest and most massive double star system to date where the two components are in contact and sharing material. The two stars in this extreme system lie about 160,000 light-years from Earth in the Large Magellanic Cloud. This intriguing system could be heading for a dramatic end, either with the formation of a single giant star or as a future binary black hole. Credit: ESO/L. Calcada

In the Large Magellanic Cloud (LMC), a satellite galaxy of the Milky Way, a staggering 160,000 light years away from Earth, astronomers using the Very Large Telescope (VLT) found the behemoth system just in the nick of time.

More massive stars, such as these, tend to be hard to spot in this kind of configuration, simply because they don’t live very long.  The starts are each emitting heat as incredible rates, with surface temperatures over 40,000 degrees Celsius.  Add in the fact that they share atmosphere and are touching, and you end up with an incredibly powerful system.

More massive blue stars tend to live for only a few hundred million years, which is a few hundred times less than their smaller, redder, stellar cousins.  Because of this, we see less blue stars, and even less in binary systems.  We see less still when we look for configurations where mergers are in the process of happening, because the mergers themselves last for such a short period of time.  These titanic stars are orbiting each other in less than a day, and yet they are over 6 million km in radius.

If they do finally merge, perhaps a few hundred or thousand years from now, they will likely produce a star so massive that it would collapse under its own gravity, except for the fact that its spinning rapidly.  This would result in a strange object that is incredibly massive but won’t explode as a supernova due to centripetal forces, called a long-duration gamma ray burst.

The other possibility is that they spin so quickly that they don’t merge at all.  You see as two objects orbiting each other move closer together, they speed up.  This is due to the conservation of angular momentum, a physical law of the universe.  If they continue to spin rapidly, they will eventually explode as separate supernova explosions, eventually becoming black holes.  The end result is a system of two black holes orbiting one another, which could then merge in the future.

Space is crazy.

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