Schedule Oct 27, 2011
The Excitation of Solar-like Oscillations in a δ Sct Star by Efficient Envelope Convection
Victoria Antoci (Univ. British Columbia)

V. Antoci, G. Handler, T. L. Campante, A. O. Thygesen, A. Moya, T. Kallinger, D. Stello, A. Grigahcène, H. Kjeldsen, T. R. Bedding, T. Lüftinger, J. Christensen-Dalsgaard, G. Catanzaro, A. Frasca, P. De Cat, K. Uytterhoeven, H. Bruntt, G. Houdek, D. W. Kurtz, P. Lenz, A. Kaiser, J. Van Cleve, C. Allen, B. D. Clarke

Helioseismology is a mature field that has led to remarkably accurate knowledge of the solar interior. With the success of the CoRoT and Kepler space missions, asteroseismology of solar-like oscillators has begun to make similar contributions to our knowledge of the interiors of stars cooler than about 6500 K. Theoretical predictions suggest that similar oscillations should exist in the hotter, more massive delta Scuti stars. However, up to now no such oscillations have been observed, seriously questioning our understanding of the physics occurring in the outer layers of these stars. Using ultra-precise data from the Kepler mission, we show the first evidence of these predicted pulsations in the ? Scuti star HD 187547, which also turned out to be a chemically peculiar Am star. Our detection made HD 187547 a unique astrophysical laboratory for testing different convective models (its effective temperature is higher than expected), study the Am phenomenon as well as investigate the interaction between the kappa-mechanism and the stochastic excitation.

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