∂ scuti stars in Praesepe. II. The STACC 1998 campaign - the spectroscopy

Abstract

We present the results of a large international spectroscopic campaign on the ∂ Scuti star BN Cnc. Combining observations from five observatories taken over more than two weeks, we calculate line indices of the H α line. A line index is the integrated line flux in a software filter divided by the continuum flux. We demonstrate that this can be used in combination with simultaneous photometry to classify the oscillation modes. We recover all the frequencies also found from photometry and assign likely mode identifications, which differ slightly from previously published values, but are found to be consistent with simple models. The difference in identification is found to have very little effect on the derived luminosity and temperature.