<P> The radial position of the condensation / evaporation front varies over time , as the nebula evolves . Occasionally , the term snow line is also used to represent the present distance at which water ice can be stable ( even under direct sunlight ) . This current snow line distance is different from the formation snow line distance during the formation of the Solar System , and approximately equals 5 AU . The reason for the difference is that during the formation of the Solar System , the solar nebula was an opaque cloud where temperatures were lower close to the Sun , and the Sun itself was less energetic . After formation , the ice got buried by infalling dust and it has remained stable a few meters below the surface . If ice within 5 AU is exposed , e.g. by a crater , then it sublimates on short timescales . However , out of direct sunlight ice can remain stable on the surface of asteroids ( and the Moon ) if it is located in permanently shadowed craters , where temperature may remain very low over the age of the Solar System ( e.g. 30 -- 40 K on the Moon ) . </P>
<P> The radial position of the condensation / evaporation front varies over time , as the nebula evolves . Occasionally , the term snow line is also used to represent the present distance at which water ice can be stable ( even under direct sunlight ) . This current snow line distance is different from the formation snow line distance during the formation of the Solar System , and approximately equals 5 AU . The reason for the difference is that during the formation of the Solar System , the solar nebula was an opaque cloud where temperatures were lower close to the Sun , and the Sun itself was less energetic . After formation , the ice got buried by infalling dust and it has remained stable a few meters below the surface . If ice within 5 AU is exposed , e.g. by a crater , then it sublimates on short timescales . However , out of direct sunlight ice can remain stable on the surface of asteroids ( and the Moon ) if it is located in permanently shadowed craters , where temperature may remain very low over the age of the Solar System ( e.g. 30 -- 40 K on the Moon ) . </P>
where is the frost line in the solar system
where is the frost line in the solar system
approximately equals 5 AU
approximately equals 5 AU