How do stars get to be four times as massive as our own sun? By exploding and then eating the products of their own firebursts.
A team of astrophysicists led by Mark Krumholz at University of California Santa Cruz have been using computers to model the behavior of proto-supermassive stars. In this video, you can see what happens when a ball of firey gas starts to turn into a supermassive star. First, the star explodes as it's forming. The explosion throws out balls of gas that turn into a star system of several massive stars orbiting the original proto-star. On the left, you can see the star system from above; on the right, you see a cutaway view from the side.
Eventually, this model predicts, the original star will eat the other stars in the system with it. And the result could be a star far more massive than the one our planet revolves around. The best part of this study is that it's basically the astrophysics equivalent of a Michael Bay movie: It's all about the behavior of REALLY GIANT explosions. In space!
What Krumholz and his team have proven here is that stars can grow larger by accretion - accumulating more matter - even after they've ignited into a ball of continuous nuclear explosions. Until recently, it was believed that stars emitted so much energy that they couldn't continue to absorb gas and other matter after they had ignited.
Big Stars Resist Dieting via Science Now