  We present HARPS spectroscopy of mu Arae (HD160691) performed for studying
the origin of the metallicity excess in this planet-hosting stars. The
asteroseismologic campaign led to the previously reported discovery of a 14
earth mass planetary companion (Santos et al. 2004). The present analysis
reinforces this interpretation by excluding other possible processes for
explaining the observed Doppler variation and leads to the identification of up
to 43 p-mode oscillations with l=0-3, frequencies in the range 1.3-2.5 mHz and
amplitudes in the range 10-40 cm/s.
