Astronomers have identified 18 extreme mass-ratio binaries in a neighboring galaxy called the Large Magellanic Cloud, pictured here. The more massive stars weigh six to 16 times as much as the Sun, while the less massive stars weigh about one to two times the Sun. We've caught them "in the delivery room," since one star is fully formed while the other is still in its infancy. These systems represent a new class of binary stars.