re: When the Sun was born...
Well, the Sun is alone, now. When we see stars they're usually in pairs or more and very often in open clusters or globular clusters.
So was it always like that?
I remember an article in Ciel et Espace wondering where the other stars were, which formed together with ours. It concluded it was going to be very difficult to find them. With Hypparcos data, it is possible to determine which star belongs to what family. But the Sun, it's another matter.