An observational asteroseismic study of the pulsating B-type stars in the open cluster NGC 884

Recent progress in the seismic interpretation of field beta Cep stars has resulted in improvements of the physical description in the stellar structure and evolution model computations of massive stars. Further asteroseismic constraints can be obtained from studying ensembles of stars in a young open cluster, which all have similar age, distance and chemical composition. We present an observational asteroseismic study based on the discovery of numerous multi-periodic and mono-periodic B-type stars in the open cluster NGC 884 (chi Persei). Our study illustrates the current status of ensemble asteroseismology of this young open cluster.