A search for non-pulsating, chemically normal stars in the δ Scuti instability strip using Kepler data
Article
Article Title | A search for non-pulsating, chemically normal stars in the δ Scuti instability strip using Kepler data |
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ERA Journal ID | 1074 |
Article Category | Article |
Authors | Murphy, Simon J. (Author), Bedding, Timothy R. (Author), Niemczura, Ewa (Author), Kurtz, Donald W. (Author) and Smalley, Barry (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 447 (4), pp. 3948-3959 |
Number of Pages | 12 |
Year | 2015 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1093/mnras/stu2749 |
Web Address (URL) | https://academic.oup.com/mnras/article/447/4/3948/1753496 |
Abstract | We identify stars in the δ Sct instability strip that do not pulsate in p modes at the 50-μmag limit, using Kepler data. Spectral classification and abundance analyses from high-resolution spectroscopy allow us to identify chemically peculiar stars, in which the absence of pulsations is not surprising. The remaining stars are chemically normal, yet they are not δ Sct stars. Their lack of observed p modes cannot be explained through any known mechanism. However, they are mostly distributed around the edges of the δ Sct instability strip, which allows for the possibility that they actually lie outside the strip once the uncertainties are taken into account. We investigated the possibility that the non-pulsators inside the instability strip could be unresolved binary systems, having components that both lie outside the instability strip. If misinterpreted as single stars, we found that such binaries could generate temperature discrepancies of ∼300 K - larger than the spectroscopic uncertainties, and fully consistent with the observations. After these considerations, there remains one chemically normal non-pulsator that lies in the middle of the instability strip. This star is a challenge to pulsation theory. However, its existence as the only known star of its kind indicates that such stars are rare. We conclude that the δ Sct instability strip is pure, unless pulsation is shut down by diffusion or another mechanism, which could be interaction with a binary companion. |
Keywords | Asteroseismology; Stars: chemically peculiar; Stars: oscillations; Stars: variables: δ Scuti; Astrophysics - Solar and Stellar Astrophysics |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Byline Affiliations | University of Sydney |
Wroclaw University, Poland | |
University of Central Lancashire, United Kingdom | |
Keele University, United Kingdom | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q73q1/a-search-for-non-pulsating-chemically-normal-stars-in-the-scuti-instability-strip-using-kepler-data
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