  Using data from observations made with XMM-Newton, we present an X-ray
analysis of two flares observed in $\xi$ Boo. The flare loop parameters are
derived using various loop models including state-of-the-art hydrodynamic flare
model. The loop lengths derived for the flaring loop structure are found to be
less than the stellar radius. The exponential decay of the X-ray light curves,
and time evolution of the plasma temperature and emission measure are similar
to those observed in compact solar flares. The X-ray light curve of post flare
phase is investigated with wavelet analysis. Wavelet analysis clearly show
oscillations of the period of 1019 s. Using the observationally estimated loop
length, density and magnetic field, the theoretically derived oscillation
period for fast-kink mode approximately matches with the observationally
estimated period. This is the first likely observational evidence of
fundamental fast-kink mode of magnetoacoustic waves in the stellar loops during
the post-flare phase of heightened emission.
