SuperWASP observations of pulsating Am stars^⋆

¹ Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK
e-mail: bs@astro.keele.ac.uk
² Jeremiah Horrocks Institute of Astrophysics, University of Central Lancashire, Preston PR1 2HE, UK
³ Department of Physics & Astronomy, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
⁴ Astrophysics Research Centre, Main Physics Building, School of Mathematics & Physics, Queen’s University, University Road, Belfast, BT7 1NN, UK
⁵ Department of Physics & Astronomy, University of Leicester, Leicester, LE1 7RH, UK
⁶ SUPA, School of Physics & Astronomy, University of St. Andrews, North Haugh, Fife, KY16 9SS, UK
⁷ Department of Physics & Astronomy, California State University, Northridge, CA, 91330, USA
⁸ NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA, 91125, USA
⁹ Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA, 93117, USA
¹⁰ Isaac Newton Group of Telescopes, Apartado de Correos 321, 38700 Santa Cruz de la Palma, Tenerife, Spain
¹¹ Department of Physics, University of Warwick, Coventry, CV4 7AL, UK

Received: 10 May 2011
Accepted: 30 June 2011

Abstract

We have studied over 1600 Am stars at a photometric precision of 1 mmag with SuperWASP photometric data. Contrary to previous belief, we find that around 200 Am stars are pulsating δ Sct and γ Dor stars, with low amplitudes that have been missed in previous, less extensive studies. While the amplitudes are generally low, the presence of pulsation in Am stars places a strong constraint on atmospheric convection, and may require the pulsation to be laminar. While some pulsating Am stars have been previously found to be δ Sct stars, the vast majority of Am stars known to pulsate are presented in this paper. They will form the basis of future statistical studies of pulsation in the presence of atomic diffusion.