Poster abstract details

Investigation of the evolutionary state of rapidly oscillating Ap (roAp) stars and comparison of their properties with non-oscillating Ap (noAp) stars provides an ultimate test of the theories of excitation of magneto-acoustic oscillations. We undertake a comprehensive study of nearly 200 roAp and noAp stars, comparing predictions of stellar structure models with the fundamental stellar parameters established with the help of new photometric temperature calibrations and improved Hipparcos parallaxes. We define precise boundaries of the observational roAp instability strip and characterize the difference in the physical properties of pulsating and constant Ap stars. This information allows us to critically evaluate predictions of different theoretical stability calculations and identify directions where theory requires improvement.