Asteroseismology of KIC 11754974: a high-amplitude SX Phe pulsator in a 343-d binary system

Murphy, S. J. and Pigulski, A. and Kurtz, D. W. and Suarez, J. C. and Handler, G. and Balona, L. A. and Smalley, B. and Uytterhoeven, K. and Szabo, R. and Thygesen, A. O. and Elkin, V. and Breger, M. and Grigahcene, A. and Guzik, J. A. and Nemec, J. M. and Southworth, J. (2013) Asteroseismology of KIC 11754974: a high-amplitude SX Phe pulsator in a 343-d binary system. Monthly Notices of the Royal Astronomical Society, 432 (3). pp. 2284-2297. ISSN 0035-8711

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The candidate SX Phe star KIC 11754974 shows a remarkably high number of combination frequencies in the Fourier amplitude spectrum: 123 of the 166 frequencies in our multifrequency fit are linear combinations of independent modes. Predictable patterns in frequency spacings are seen in the Fourier transform of the light curve. We present an analysis of 180 d of short-cadence Kepler photometry and of new spectroscopic data for this evolved, late A-type star. We infer from the 1150-d, long-cadence light curve, and in two different ways, that our target is the primary of a 343-d, non-eclipsing binary system. According to both methods, the mass function is similar, f (M) = 0.0207 ± 0.0003M⊙. The observed pulsations are modelled extensively, using separate, state-of-the-art, time-dependent convection (TDC) and rotating models. The models match the observed temperature and low metallicity, finding a mass of 1.50-1.56M⊙. The models suggest that the whole star is metal poor, and that the low metallicity is not just a surface abundance peculiarity. This is the best frequency analysis of an SX Phe star, and the only Kepler δ Sct star to be modelled with both TDC and rotating models.

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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: 27 Apr 2022 00:31
Last Modified: 27 Apr 2022 00:31
Uncontrolled Keywords: Asteroseismology; Stars: individual: KIC 11754974; Stars: oscillations; Stars: population II; Stars: variables: δ scuti; Astrophysics - Solar and Stellar Astrophysics
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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