MULTIPLICITY AND THE AGES OF THE STARS IN THE TAURUS STAR-FORMING REGION

Ages for the pre-main-sequence stars in the Taurus star-forming region now known to be multiples are systematically younger than the ages of the singles. This seems to be an artifact. Overestimating the stellar luminosity in an unresolved multiple whose components are on Hayashi tracks produces an underestimate of the system's age. Until the astrop hysical parameters of the components in the multiples become better kn own, the published age estimates for the single stars should be more a ccurate. Their average age is 2-3 times that of the multiples regarded as unresolved objects. Since most of the stars in the Taurus star-for ming region are in multiples, the average age of the entire group of s tars is 2-3 times older than previously thought. This result applies t o both the strong and weak emission-line pre-main-sequence stars. The implications of a longer phase of pre-main-sequence activity are discu ssed.