If you accept the text of Matthew’s Gospel as a definitive, true narration of the Magi, a few things are clear. For one thing, the “star” isn’t any kind of unusual phenomenon like a comet or supernova, or a mysterious ball of gas in the atmosphere. It had to be some kind of celestial event or events that was visible to anyone, but was subject to an interpretation by someone with the wisdom to understand what he was looking at. In Matthew, 2:7, Herod had to ask the Magi when the “star” had appeared in the sky. If it had been something extraordinary like a comet or supernova, he wouldn’t have needed to ask this because he would have been able to see it himself.
Where is Carl Sagan when you need him? :o)