U. Feldman et Jm. Laming, Element abundances in the upper atmospheres of the sun and stars: Update of observational results, PHYS SCR, 61(2), 2000, pp. 222-252
We review observational progress in the determination of element abundances
in the solar corona, largely due to the new capabilities offered by the in
strumentation on the SOHO satellite. Many new facets to coronal abundance a
nomalies with respect to the photosphere are revealed. This includes new re
sults on the FIP (First Ionization Potential) Effect, whereby elements with
FIP < 10 eV are enriched in the corona by a factor similar to 4 with respe
ct to the photosphere, and the first evidence for gravitational settling of
heavy elements in the corona.
Advances in EUV and X-ray astronomy instrumentation have also yielded the f
irst spectra of stellar coronae of sufficient quality to allow element abun
dance measurements. We survey these new results and compare the various ste
llar cases to the solar corona.