2008MNRAS.387.1627P

We present temporal and spectral characteristics of X-ray flares observed from six late-type G-K active dwarfs (V368Cep, XIBoo, IMVir, V471Tau, CCEri and EPEri) using data from observations with the XMM-Newton observatory. All the stars were found to be flaring frequently and altogether a total of 17 flares were detected above the `quiescent' state X-ray emission which varied from 0.5 to 8.3x10<sup>29</sup>erg/s. The largest flare was observed in a low-activity dwarf XIBoo with a decay time of 10ks and ratio of peak flare luminosity to `quiescent' state luminosity of 2. We have studied the spectral changes during the flares by using colour-colour diagram and by detailed spectral analysis during the temporal evolution of the flares. 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. We have derived the semiloop lengths of flares based on the hydrodynamic flare model. The size of the flaring loops is found to be less than the stellar radius. The hydrodynamic flare decay analysis indicates the presence of sustained heating during the decay of most flares.