Paunzen, E and Skarka, M and Holdsworth, DL and Smalley, B and West, RG (2014) HD 54272, a classical lambda Bootis star and gamma Doradus pulsator. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 440 (2). 1020 - 1026. ISSN 0035-8711

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Abstract

We detect the second known λ Bootis star (HD 54272) which exhibits γ Doradus-type pulsations. The star was formerly misidentified as a RR Lyrae variable. The λ Bootis stars are a small group (only 2 per cent) of late B to early F-type, Population I stars which show moderate to extreme (up to a factor 100) surface underabundances of most Fe-peak elements and solar abundances of lighter elements (C, N, O, and S). The photometric data from the Wide Angle Search for Planets (WASP) and All Sky Automated Survey (ASAS) projects were analysed. They have an overlapping time base of 1566 d and 2545 d, respectively. Six statistically significant peaks were identified (f1 = 1.410 116 d−1, f2 = 1.283 986 d−1, f3 = 1.293 210 d−1, f4 = 1.536 662 d−1, f5 = 1.157 22 d−1 and f6 = 0.226 57 d−1). The spacing between f1 and f2, f1 and f4, f5 and f2 is almost identical. Since the daily aliasing is very strong, the interpretation of frequency spectra is somewhat ambiguous. From spectroscopic data, we deduce a high rotational velocity (250 ± 25 km s−1) and a metal deficiency of about −0.8 to −1.1 dex compared to the Sun. A comparison with the similar star, HR 8799, results in analogous pulsational characteristics but widely different astrophysical parameters. Since both are λ Bootis-type stars, the main mechanism of this phenomenon, selective accretion, may severely influence γ Doradus-type pulsations.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2014 Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: techniques: photometric / stars: chemically peculiar / stars: individual: HD 54272 / stars: variables: Scuti / stars: variables: RR Lyrae
Subjects: Q Science > QB Astronomy
?? stars: chemically peculiar ??
?? stars: individual: HD 54272 ??
?? stars: variables: RR Lyrae ??
?? stars: variables: delta Scuti ??
?? techniques: photometric ??
Divisions: Faculty of Natural Sciences > School of Physical and Geographical Sciences
Related URLs:
Depositing User: Symplectic
Date Deposited: 13 Jul 2016 15:36
Last Modified: 13 Jul 2016 15:36
URI: http://eprints.keele.ac.uk/id/eprint/2019

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