From solar observations we know that the corona has different elemental composition from that of the photosphere. In the solar corona elements of low first ionisation potential (FIP) are enhanced by a factor of three to four compared to their photospheric abundances. Recent observations showed inverse FIP (i.e. enhanced abundances of high FIP elements) regions near sunspots in flare spectra taken by Hinode/EIS in the EUV. Inverse FIP coronal composition has been observed on stars, mainly of K and M spectral type.

The Sun in different wavelengths (credit: SDO).

The workshop is aimed at comparing the characteristics and conditions under which inverse FIP effect is observed on the Sun to those on stars with inverse-FIP corona. To date, there is only one model, which is able to explain FIP and inverse FIP coronal abundances in a consistent way (Laming, Living Rev. Solar Phys., 12:2, 2015), which invokes the ponderomotive force giving rise to ion-neutral separation in stellar chromospheres.

The FIP effect vs the spectral type. (Brooks et al. 2017, Nature Comm.).