Abundance analysis from emission lines

Abstract. Coronal abundances have been a subject of debate in the last years due to the availability of high-quality X-ray spectra of many cool stars. Coronal abundance determinations have generally been compared to solar photospheric abundances from this a number of general properties have been inferred, such as the presence of a coronal metal depletion with an inverse First Ionization Potential dependence, with a functional form dependent on the activity level. We report a detailed analysis of the coronal abundance of 4 stars with various levels of activity and with accurately known photospheric abundances. The coronal abundance is determined using a line flux analysis and a full determination of the differential emission measure. We show that, when coronal abundances are compared with real photospheric values for the individual stars, the resulting pattern can be very different some active stars with apparent Metal Abundance Deficiency in the corona have coronal abundances that are actually consistent with their photospheric counterparts. 

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