In search of the Ap instability strip

  • Jaymie M. Matthews
Part IV Seismology of the Stars
Part of the Lecture Notes in Physics book series (LNP, volume 367)


The lack of a definite excitation mechanism for the rapidly oscillating Ap (roAp) stars has hampered both the understanding of these p-mode pulsators and the photometric search for new members of the class. In an effort to identify an empirical ‘instability strip’ for the class, Strömgren colours (b-y, u-b, [m1], [c1], and β) of the roAp stars have been compared to colour-colour distributions of large samples of Ap stars (Vogt and Faundez 1979) and spectroscopically normal δ Scuti stars (Breger 1979). The loci of roAp stars are best defined in the [c1]-[u-b], [c1]-(b-y) and [c1-[m1] planes. The [c1-(b-y) diagram suggests that roAp stars cover a range in luminosity comparable to the δ Scuti stars and share a common spectroscopic peculiarity more specific than the SrCrEu subclass to which they belong.


Chemical Peculiarity Main Sequence Star Monthly Notice Normal Star Peculiar Star 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Jaymie M. Matthews
    • 1
  1. 1.Department of Geophysics and AstronomyUniversity of British ColumbiaVancouverCanada

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