"Evidence from the Bible and astronomy suggests that the Star of Bethlehem was a comet which was visible in 5 BC, and described in ancient Chinese records. A comet uniquely fits the description in Matthew of a star which newly appeared, which travelled slowly through the sky against the star background and which 'stood over' Bethlehem. The evidence points to Jesus being bom in the period 9 March-4 May, 5 BC, probably around Passover time: 13-27 April, 5 BC. Birth in the spring is consistent with the account in Luke that there were shepherds living out in the fields nearby keeping watch over their flock by night. Birth in 5 BC also throws light upon the problem of the census of Caesar Augustus. A new chronology of the life of Christ is given which is consistent with the available evidence. This chronology suggests that Christ died close to his 37th birthday."
More: http://www.asa3.org/ASA/topics/Astronomy-Cosmology/S&CB%2010-93Humphreys.html
No, for obvious reasons already stated, it was most likely NOT a comet.
You're 6 months off. The Lord was born on the day that had been prepared to foretell his coming: Rosh Hashanna, which was September 29, 4 B.C. which fits in perfectly with all other known facts of the time, both Biblical, and secular history too. Pasover foretold his death.