The Distance to the Crab Nebula and NP 0532

Abstract

Twelve lines of evidence bearing on the determination of the distance to the Crab nebula and NP 0532 are discussed. Some of these depend on the dynamics of the nebular expansion, some on physical processes in the supernova or its remnant, and some on the nature of the intervening interstellar medium. An unweighted average of the various methods yields a distance of about 1930 pc.