Mode identification and asteroseismology of δ Scuti stars

The use of multicolour photometry for mode identification in pulsating stars is discussed. We present a new, statistically based, algorithm for finding the best estimate of the spherical harmonic degree, and a confidence level from which the uniqueness can be ascertained. The method is applied to some well-observed delta Sct stars with multicolour photometry. We also propose an algorithm to deduce the effective temperature, luminosity and equatorial velocity from the observed frequencies. We find that fixing the modes of at least some frequencies is essential for a unique solution. The method is applied to a subset of the delta Sct stars which have a suitable number of frequencies and mode identifications.