The Snow Line (also called the Frost Line, Ice Line, or Water Line) is the distance from a Protostar at which Ice can form and Ammonia and Methane can condense. The Temperature is estimated at 150K, i.e., in the 145K to 170K range for a typical Protoplanetary Disk. The solar systems' Snow Line is about 5 AU, nearly to Jupiter. In a general way, the Snow Line forms the outer bound of the Habitable Zone.
Habitable Zone (HZ)