Song, InseokZuckerman, BBessell, Michael2015-12-132015-12-130004-637Xhttp://hdl.handle.net/1885/87560Chromospheric emission in the Ca II H and K lines has often been used as an age diagnostic for solar mass stars. For 20 such stars with ages less than a few hundred megayears, we compare Ca II ages derived by Wright et al. with ages we derive based on a combination of lithium abundance, X-ray activity, and Galactic space motion. Typically, the Ca II ages are noticeably older than the lithium/X-ray ages, suggesting that a recalibration of the Ca II ages may be necessary.Keywords: Stars: activity; Stars: fundamental parameters200410.1086/4256832015-12-12