THE DISCOVERY OF NONRADIAL PULSATION IN THE LAMBDA-BOOTIS-STAR HD-111604

Evidence for high order nonradial pulsation (NRP) has been discovered in the lambda Boo star HD 111604. Analysis of a limited number of spec tra of the Na I D lines indicate that the mode of oscillation, \m\, is approximately 20 and NRP features circumnavigate the star every 0.71 days. Current models suggest that these objects should be near the ZAM S, and the detection of nonradial pulsation in at least one member of the class presents the exciting possibility of performing a direct mea surement of its evolutionary state to test this hypothesis.