THE ANGULAR DIAMETER OF k BOÖTIS

Using the CHARA Array and the Palomar Testbed Interferometer, the chemically peculiar star k Boötis has been spatially resolved.We havemeasured the limb darkened angular diameter to be LD 1⁄4 0:533 0:029mas, corresponding to a linear radius of R? 1⁄4 1:70 0:10R . Themeasured angular diameter yields an effective temperature for kBoo of TeA 1⁄4 8887 242 K. Based on literature surface gravity estimates spanning log g 1⁄4 4:0 4:2 cm s , we have derived a stellar mass range of M? 1⁄4 1:1 1:7M . For a given surface gravity, the linear radius uncertainty contributes approximately (M?) 1⁄4 0:1 0:2M to the total mass uncertainty. The uncertainty in themass (i.e., the range of derived masses) is primarily a result of the uncertainty in the surface gravity. The upper bound of our derived mass range (log g 1⁄4 4:2, M? 1⁄4 1:7 0:2 M ) is consistent with 100–300 Myr solar metallicity evolutionary models. The midrange of our derived masses (log g 1⁄4 4:1, M? 1⁄4 1:3 0:2 M ) is consistent with 2–3 Gyr metal-poor evolutionary models. A more definitive surface gravity determination is required to determine a more precise mass for k Boo. Subject headingg s: circumstellar matter — infrared: stars — stars: fundamental parameters — stars: individual (k Boötis) — techniques: interferometric