Pulsation versus metallicism in Am stars as revealed by LAMOST and WASP

B. Smalley; V. Antoci; D. L. Holdsworth; D. W. Kurtz; S. J. Murphy; P. De Cat; D. R. Anderson; G. Catanzaro; A.  Collier Cameron; C. Hellier; P. F. L. Maxted; A. J. Norton; D. Pollacco; V. Ripepi; R. G. West; P. J. Wheatley

doi:10.1093/mnras/stw2903

Pulsation versus metallicism in Am stars as revealed by LAMOST and WASP

B. Smalley, V. Antoci, D. L. Holdsworth, D. W. Kurtz, S. J. Murphy, P. De Cat, D. R. Anderson, G. Catanzaro, A. Collier Cameron, C. Hellier, P. F. L. Maxted, A. J. Norton, D. Pollacco, V. Ripepi, R. G. West, P. J. Wheatley

Research output: Contribution to journal › Article › peer-review

Abstract

We present the results of a study of a large sample of A and Am stars with spectral types from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and light curves from Wide Area Search for Planets (WASP). We find that, unlike normal A stars, δ Sct pulsations in Am stars are mostly confined to the effective temperature range 6900 < T_eff < 7600 K. We find evidence that the incidence of pulsations in Am stars decreases with increasing metallicism (degree of chemical peculiarity). The maximum amplitude of the pulsations in Am stars does not appear to vary significantly with metallicism. The amplitude distributions of the principal pulsation frequencies for both A and Am stars appear very similar and agree with results obtained from Kepler photometry. We present evidence that suggests turbulent pressure is the main driving mechanism in pulsating Am stars, rather than the κ-mechanism, which is expected to be suppressed by gravitational settling in these stars.

Original language	English
Pages (from-to)	2662-2670
Number of pages	9
Journal	Monthly Notices of the Royal Astronomical Society
Volume	465
Issue number	3
Early online date	10 Nov 2016
DOIs	https://doi.org/10.1093/mnras/stw2903
Publication status	Published - 1 Mar 2017

Keywords

Asteroseismology
Techniques: photometric
Stars: chemically peculiar
Stars: oscillations
Stars: variables: δ Scuti

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10.1093/mnras/stw2903

Cameron_2016_MNRAS_AMstars_FinalPublishedVersion
© 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at: https://dx.doi.org/10.1093/mnras/stw2903
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Astronomy at St Andrews 2015-2018: Astronomy at St Andrews 2015-2018
Jardine, M. (PI), Cameron, A. (CoI), Cyganowski, C. (CoI), Horne, K. (CoI) & Wood, K. (CoI)
Science & Technology Facilities Council
1/04/15 → 31/03/18
Project: Standard

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Smalley, B., Antoci, V., Holdsworth, D. L., Kurtz, D. W., Murphy, S. J., De Cat, P., Anderson, D. R., Catanzaro, G., Collier Cameron, A., Hellier, C., Maxted, P. F. L., Norton, A. J., Pollacco, D., Ripepi, V., West, R. G., & Wheatley, P. J. (2017). Pulsation versus metallicism in Am stars as revealed by LAMOST and WASP. Monthly Notices of the Royal Astronomical Society, 465(3), 2662-2670. https://doi.org/10.1093/mnras/stw2903

@article{d739ac9881d944b68d8e9af53bf2cfbb,

title = "Pulsation versus metallicism in Am stars as revealed by LAMOST and WASP",

abstract = "We present the results of a study of a large sample of A and Am stars with spectral types from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and light curves from Wide Area Search for Planets (WASP). We find that, unlike normal A stars, δ Sct pulsations in Am stars are mostly confined to the effective temperature range 6900 < Teff < 7600 K. We find evidence that the incidence of pulsations in Am stars decreases with increasing metallicism (degree of chemical peculiarity). The maximum amplitude of the pulsations in Am stars does not appear to vary significantly with metallicism. The amplitude distributions of the principal pulsation frequencies for both A and Am stars appear very similar and agree with results obtained from Kepler photometry. We present evidence that suggests turbulent pressure is the main driving mechanism in pulsating Am stars, rather than the κ-mechanism, which is expected to be suppressed by gravitational settling in these stars.",

keywords = "Asteroseismology, Techniques: photometric, Stars: chemically peculiar, Stars: oscillations, Stars: variables: δ Scuti",

author = "B. Smalley and V. Antoci and Holdsworth, {D. L.} and Kurtz, {D. W.} and Murphy, {S. J.} and {De Cat}, P. and Anderson, {D. R.} and G. Catanzaro and {Collier Cameron}, A. and C. Hellier and Maxted, {P. F. L.} and Norton, {A. J.} and D. Pollacco and V. Ripepi and West, {R. G.} and Wheatley, {P. J.}",

note = "The WASP project is funded and operated by Queen{\textquoteright}s University Belfast, the Universities of Keele, St Andrews and Leicester, the Open University, the Isaac Newton Group, the Instituto de Astrofisica de Canarias, the South African Astronomical Observatory and by the UK Science and Technology Facilities Council (STFC). Funding for the Stellar Astrophysics Centre was provided by the Danish National Research Foundation (grant no. DNRF106). The research is supported by the ASTERISK project (ASTERoseismic Investigations with SONG and Kepler) funded by the European Research Council (grant agreement no. 267864). DWK is supported by the STFC.DLH acknowledges support from the STFC via grant number ST/M000877/1. SJM was supported by the Australian Research Council.",

year = "2017",

month = mar,

day = "1",

doi = "10.1093/mnras/stw2903",

language = "English",

volume = "465",

pages = "2662--2670",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press",

number = "3",

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Smalley, B, Antoci, V, Holdsworth, DL, Kurtz, DW, Murphy, SJ, De Cat, P, Anderson, DR, Catanzaro, G, Collier Cameron, A, Hellier, C, Maxted, PFL, Norton, AJ, Pollacco, D, Ripepi, V, West, RG & Wheatley, PJ 2017, 'Pulsation versus metallicism in Am stars as revealed by LAMOST and WASP', Monthly Notices of the Royal Astronomical Society, vol. 465, no. 3, pp. 2662-2670. https://doi.org/10.1093/mnras/stw2903

TY - JOUR

T1 - Pulsation versus metallicism in Am stars as revealed by LAMOST and WASP

AU - Smalley, B.

AU - Antoci, V.

AU - Holdsworth, D. L.

AU - Kurtz, D. W.

AU - Murphy, S. J.

AU - De Cat, P.

AU - Anderson, D. R.

AU - Catanzaro, G.

AU - Collier Cameron, A.

AU - Hellier, C.

AU - Maxted, P. F. L.

AU - Norton, A. J.

AU - Pollacco, D.

AU - Ripepi, V.

AU - West, R. G.

AU - Wheatley, P. J.

N1 - The WASP project is funded and operated by Queen’s University Belfast, the Universities of Keele, St Andrews and Leicester, the Open University, the Isaac Newton Group, the Instituto de Astrofisica de Canarias, the South African Astronomical Observatory and by the UK Science and Technology Facilities Council (STFC). Funding for the Stellar Astrophysics Centre was provided by the Danish National Research Foundation (grant no. DNRF106). The research is supported by the ASTERISK project (ASTERoseismic Investigations with SONG and Kepler) funded by the European Research Council (grant agreement no. 267864). DWK is supported by the STFC.DLH acknowledges support from the STFC via grant number ST/M000877/1. SJM was supported by the Australian Research Council.

PY - 2017/3/1

Y1 - 2017/3/1

N2 - We present the results of a study of a large sample of A and Am stars with spectral types from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and light curves from Wide Area Search for Planets (WASP). We find that, unlike normal A stars, δ Sct pulsations in Am stars are mostly confined to the effective temperature range 6900 < Teff < 7600 K. We find evidence that the incidence of pulsations in Am stars decreases with increasing metallicism (degree of chemical peculiarity). The maximum amplitude of the pulsations in Am stars does not appear to vary significantly with metallicism. The amplitude distributions of the principal pulsation frequencies for both A and Am stars appear very similar and agree with results obtained from Kepler photometry. We present evidence that suggests turbulent pressure is the main driving mechanism in pulsating Am stars, rather than the κ-mechanism, which is expected to be suppressed by gravitational settling in these stars.

AB - We present the results of a study of a large sample of A and Am stars with spectral types from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and light curves from Wide Area Search for Planets (WASP). We find that, unlike normal A stars, δ Sct pulsations in Am stars are mostly confined to the effective temperature range 6900 < Teff < 7600 K. We find evidence that the incidence of pulsations in Am stars decreases with increasing metallicism (degree of chemical peculiarity). The maximum amplitude of the pulsations in Am stars does not appear to vary significantly with metallicism. The amplitude distributions of the principal pulsation frequencies for both A and Am stars appear very similar and agree with results obtained from Kepler photometry. We present evidence that suggests turbulent pressure is the main driving mechanism in pulsating Am stars, rather than the κ-mechanism, which is expected to be suppressed by gravitational settling in these stars.

KW - Asteroseismology

KW - Techniques: photometric

KW - Stars: chemically peculiar

KW - Stars: oscillations

KW - Stars: variables: δ Scuti

U2 - 10.1093/mnras/stw2903

DO - 10.1093/mnras/stw2903

M3 - Article

SN - 0035-8711

VL - 465

SP - 2662

EP - 2670

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 3

ER -

Pulsation versus metallicism in Am stars as revealed by LAMOST and WASP

Abstract

Keywords

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Astronomy at St Andrews 2015-2018: Astronomy at St Andrews 2015-2018

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