Hi Anuram, Our Sun is one of billions of stars in the galaxy. Most of the stars you see when you look up at the night sky are actually made up of more than one star. These are called "binary star systems" -- they are two stars (or more!) that rotate around each other and look like one star to the naked eye. If you look at them through a high-power telescope, though, you'll see both stars. If the two binary stars in a system are close enough and big enough, they can interact in other ways besides just orbiting each other. For example, one of the stars can gradually "pull off" material from the other star. This is called accretion. Sometimes, a star can accrete enough material from its neighbor that it becomes large enough to have a supernova (a huge explosion). So the interaction between stars can lead to some dramatic consequences. As for our star (the Sun), it doesn't have a companion star...at least one that can be seen. There are those who think that the Sun could be part of a binary system, but there's no strong evidence for this. For now, our Sun is a lonely star. Lindsay