Period spacings of γ Doradus pulsators in the Kepler field: detection methods and application to 22 slow rotators

Li, Gang and Bedding, Timothy R. and Murphy, Simon J. and Van Reeth, Timothy and Antoci, Victoria and Ouazzani, Rhita-Maria (2018) Period spacings of γ Doradus pulsators in the Kepler field: detection methods and application to 22 slow rotators. Monthly Notices of the Royal Astronomical Society, 482 (2). pp. 1757-1785. ISSN 0035-8711

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In γ Doradus (γ Dor) stars, the g-mode period spacing shows an approximately linear relation with period. The slope is a new asteroseismic diagnostic, related to the rotation rate and the azimuthal order m. We report two automated methods, the ‘moving-window Fourier transform’ and the ‘cross-correlation’, to detect and measure the period spacings based on 4-yr light curves from the Kepler satellite. The results show that the cross-correlation method performs better at detecting the period spacings and their slopes. In this paper, we apply our method to 22 γ Dor stars with g-mode multiplets split by rotation. The rotation periods are similar to the g-mode period spacings, causing the multiplets to overlap. To clarify the overlapping patterns, we use the échelle diagram and introduce a ‘copy-shift’ diagram to discern and measure the splittings. The first observational relation between slopes and splittings is shown. The slope deviates from zero when the splitting increases, as the theory predicts. We found that what appears to be rotational splittings in two stars is in fact caused by two nearly identical overlapping patterns from binaries.

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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 23:58
Last Modified: 30 May 2022 03:49
Uncontrolled Keywords: Asteroseismology; Stars: rotation; Stars: variables: general; 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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