Introduction

The Pleiades is a galactic star cluster in the same neighborhood of the Milkyway as the Sun. Its distance from us has been determined by ground based measurements of parallax, and parallax measurements from space using the Hipparcos satellite and the Hubble Space Telescope. A recent paper by Soderblom et al. (Ap.J. 129, 1616-1624 (1005)) gave a best-estimate for its distance of $133.5 \pm 1.2$ parsecs, significantly farther than the Hipparcos measurement of $118 \pm 4$. Since all members of a cluster should be nearly the same age and composition, the Pleiades is very useful for testing models of stellar structure and evolution. For this purpose we need to know its distance.

An alternative approach to using parallax is to fit the main sequence to the expected color-magnitude curve for a cluster of zero age. Here we will apply this method to the Pleiades using published photometric measurements of its stars and a theoretical zero-age main sequence (ZAMS) color-magnitude relationship.