  We present first results from five XMM-Newton observations of the binary
system Alpha Centauri, which has been observed in snapshot like exposures of
roughly two hours each during the last two years. In all our observations the
X-ray emission of the system is dominated by Alpha Cen B, a K1 star. The
derived light curves of the individual components reveal variability on short
timescales and a flare was discovered on Alpha Cen B during one observation. A
PSF fitting algorithm is applied to the event distribution to determine the
brightness of each component during the observations. We perform a spectral
analysis with multi-temperature models to calculate the X-ray luminosities.We
investigate long term variability and possible activity cycles of both stars
and find the optically brighter component Alpha Cen A, a G2 star very similar
to our Sun, to have fainted in X-rays by at least an order of magnitude during
the observation program, a behaviour never observed before on Alpha Cen A, but
rather similar to the X-ray behaviour observed with XMM-Newton on HD 81809. We
also compare our data with earlier spatially resolved observations performed
over the last 25 years.
