Gaia-derived luminosities of Kepler A/F stars and the pulsator fraction across the δ Scuti instability strip

Murphy, Simon J. and Hey, Daniel and Van Reeth, Timothy and Bedding, Timothy R. (2019) Gaia-derived luminosities of Kepler A/F stars and the pulsator fraction across the δ Scuti instability strip. Monthly Notices of the Royal Astronomical Society, 485 (2). pp. 2380-2400. ISSN 0035-8711

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We study the fraction of stars in and around the δ Scuti instability strip that are pulsating, using Gaia DR2 parallaxes to derive precise luminosities. We classify a sample of over 15 000 Kepler A and F stars into δ Sct and non-δ Sct stars, paying close attention to variability that could have other origins. We find that 18 per cent of the δ Sct stars have their dominant frequency above the Kepler long-cadence Nyquist frequency (periods < 1 h), and 30 per cent have some super-Nyquist variability. We analyse the pulsator fraction as a function of effective temperature and luminosity, finding that many stars in the δ Sct instability strip do not pulsate. The pulsator fraction peaks at just over 70 per cent in the middle of the instability strip. The results are insensitive to the amplitude threshold used to identify the pulsators. We define a new empirical instability strip based on the observed pulsator fraction that is systematically hotter than theoretical strips currently in use. The stellar temperatures, luminosities, and pulsation classifications are provided in an online catalogue.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©:2019 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 07 Jul 2022 23:28
Last Modified: 11 Jul 2022 03:01
Uncontrolled Keywords: asteroseismology, parallaxes, Hertzsprung-Russell and colour-magnitude diagrams, stars: oscillations, 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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