Line profile analysis of the delta Scuti star HD 2724 BB Phe: mode identification and amplitude variations

The line profile variations of the delta Scuti star HD 2724=BB Phe were stu died on the basis of new 189 high-resolution spectrograms covering 52 hours of observations on a baseline of 8.3 days. By combining these results with those of a previous campaign 13 pulsation modes were identified: 5 of them are both photometric and spectroscopic, 3 are purely spectroscopic and 5 p urely photometric. For the first time it was possible to compare spectrosco pic data taken in two different seasons: 6 modes were found to be common to both datasets and furthermore strong amplitude variations of the excited m odes were detected. The fit of the line profile variations with a model of non-radial pulsating star allowed us to obtain a reasonable estimate of the inclination of the rotational axis and to propose the l, m typing of the s pectroscopic modes. The frequency content resembles that of 4 CVn, a delta Sct star with similar physical parameters.