The role of turbulent pressure as a coherent pulsational driving mechanism: The case of the δ SCUTI STAR HD 187547

Antoci, V. and Cunha, M. and Houdek, G. and Kjeldsen, H. and Trampedach, R. and Handler, G. and Luftinger, T. and Arentoft, T. and Murphy, S. (2014) The role of turbulent pressure as a coherent pulsational driving mechanism: The case of the δ SCUTI STAR HD 187547. The Astrophysical Journal, 796 (2):118. pp. 1-8. ISSN 1538-4357

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HD 187547 was the first candidate that led to the suggestion that solar-like oscillations are present in δ Scuti stars. Longer observations, however, show that the modes interpreted as solar-like oscillations have either very long mode lifetimes, longer than 960 days, or are coherent. These results are incompatible with the nature of 'pure' stochastic excitation as observed in solar-like stars. Nonetheless, one point is certain: the opacity mechanism alone cannot explain the oscillation spectrum of HD 187547. Here we present new theoretical investigations showing that convection dynamics can intrinsically excite coherent pulsations in the chemically peculiar δ Scuti star HD 187547. More precisely, it is the perturbations of the mean Reynold stresses (turbulent pressure) that drives the pulsations and the excitation takes place predominantly in the hydrogen ionization zone.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: File reproduced in accordance with the copyright policy of the publisher/author.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 02 May 2022 23:07
Last Modified: 02 May 2022 23:07
Uncontrolled Keywords: Asteroseismology; Convection; Stars: individual (HD 187546); Stars: oscillations; Stars: variables: delta Scuti
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Socio-Economic Objectives (2020): 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280120 Expanding knowledge in the physical sciences
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