region was used to minimise the significant subtracted background. A larger (45 arcsec) extraction radius for the brightest source was used to check that the smaller extraction radius did not change the derived spectral parameters. The same filtering expression used to generate the images was used for source extraction. For 9 of the stars spectra were obtained from all three EPIC instruments. Star 11 lay in a region of the pn detector which was excluded by the selection expression described earlier, and thus only MOS data were used for this star. Annuli around each source were used to estimate the background.

Redistribution and ancillary response matrices were generated using the [rmfgen]{} and [arfgen]{} tasks. One matrix was generated per instrument (based on star 3) and then used for each of the stars. Energy ranges above 0.3keV were considered in the analysis, but the spectra were binned such that there were at least ten source counts per bin and then modelled using [xspec]{}.

A single optically thin thermal plasma ([mekal]{} – Mewe, Kaastra & Liedahl 1995) component modified by photoelectric absorption (a 1-T model) was used as an initial model. The column density of the absorption was fixed at $3\times10^{20}$cm$^{-2}$. This 