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High-Speed Photometry of Bright roAp Stars With Small Telescopes

Published online by Cambridge University Press:  12 April 2016

D.W. Kurtz
D.W. Kurtz*
Affiliation:
Centre for Astrophysics, University of Central Lancashire, Preston PR1 2HE, UK Department of Astronomy, University of Cape Town, Rondebosch 7701, South Africa Laboratoire d’Astrophysique, Observatoire Midi Pyrenees, 14 Av. Eduoard Belin, 31400 Toulouse, France

Abstract

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The rapidly oscillating Ap stars are magnetic peculiar A stars which pulsate in multiple p modes with periods in the range of about 6 to 16 minutes with their oscillation axes aligned with the oblique magnetic axes of the stars. Some of these stars have the richest frequency spectra of any non-degenerate stars other than the sun. This paper shows how photometric observations using small telescopes can be used to work on several astrophysically interesting problems posed by these stars. An example of high precision photometry is shown. The proof of oblique dipole pulsation, the distortion of pulsation modes (probably by the magnetic field), and the determination of asteroseismic luminosities are all discussed. The latter, especially when combined with new theoretical developments concerning magnetic field-pulsation interaction, suggests that Ap stars have lower effective temperatures and/or smaller radii than has been previously thought. It is pointed out that this may be related to the recently discovered extreme discrepancy in effective temperature determined from the wings and cores of the Hα line.

Type
V. Variability Study
Information
International Astronomical Union Colloquium , Volume 183: Small-Telescope Astronomy on Global Scales , 2001 , pp. 187 - 196
Copyright
Copyright © Astronomical Society of the Pacific 2001

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