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The Solar First Ionization Potential (FIP) effect, where low-FIP elements areenriched in the corona relative to the photosphere, while high-FIP abundancesremain unchanged, has been known for a long while. High resolution X-rayspectroscopy has revealed that active stellar coronae show an opposite effect,which was labeled the Inverse-FIP (IFIP) effect. The correlation found betweencoronal activity and the FIP/IFIP bias suggested perhaps that flaring activityis involved in switching from FIP to IFIP. This work aims at a more systematicunderstanding of the FIP trends during stellar flares and complements anearlier study based on Chandra alone. The eight brightest X-ray flares observedwith XMM-Newton are analyzed and compared with their respective quiescencestates. Together with six previous flares observed with Chandra, thisestablishes the best currently available sample of flares. We look forabundance variations during the flare and their correlation with FIP. For thatpurpose, we define a new FIP bias measure. A trend is found where coronae thatare IFIP biased in quiescence, during flares show a FIP bias with respect totheir quiescence composition. This effect is reversed for coronae that are FIPbiased in quiescence. The observed trend is thus consistent with chromosphericevaporation rather than with a FIP mechanism operating during flares. It alsosuggests that the quiescent IFIP bias is real and that the large flares are notthe direct cause of the IFIP effect in stellar coronae.

Abundance variations and first ionization potential trends during large stellar flares