Kahraman Aliçavuş, F, Poretti, E, Catanzaro, G, Smalley, B ORCID: https://orcid.org/0000-0002-3456-087X, Niemczura, E, Rainer, M and Handler, G (2020) Spectroscopy of hot γ Doradus and A–F hybrid Kepler candidates close to the hot border of the δ Scuti instability strip. Monthly Notices of the Royal Astronomical Society, 493 (3). 4518 - 4532.

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Abstract

If γ Dor-type pulsations are driven by the convective blocking mechanism, a convective envelope at a sufficient depth is essential. There are several hot γ Dor and hybrid star candidates in which there should not be an adequate convective envelope to excite the γ Dor-type oscillations. The existence of these hot objects needs an explanation. Therefore, we selected, observed, and studied 24 hot γ Dor and hybrid candidates to investigate their properties. The atmospheric parameters, chemical abundances, and vsin i values of the candidates were obtained using medium-resolution (R = 46 000) spectra taken with the Fibre-fed Échelle Spectrograph instrument mounted at the Nordic Optical Telescope. We also carried out frequency analyses of the Kepler long- and short-cadence data to determine the exact pulsation contents. We found only five bona fide hot γ Dor and three bona fide hot hybrid stars in our sample. The other 16 stars were found to be normal γ Dor, δ Sct, or hybrid variables. No chemical peculiarity was detected in the spectra of the bona fide hot γ Dor and hybrid stars. We investigated the interplay between rotation and pulsational modes. We also found that the hot γ Dor stars have higher Gaia luminosities and larger radii compared to main-sequence A–F stars.

Item Type: Article
Additional Information: © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
Uncontrolled Keywords: stars: abundances, stars: atmospheres, stars: general, stars: oscillations, stars: rotation
Subjects: Q Science > QB Astronomy
Q Science > QB Astronomy > QB460 Astrophysics
Q Science > QB Astronomy > QB799 Stars
Q Science > QC Physics
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 07 May 2020 08:19
Last Modified: 07 May 2020 08:19
URI: https://eprints.keele.ac.uk/id/eprint/7937

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