Solar Physics Division Meeting 2000, June 19-22
Session 13. Solar Corona
Oral, Chair: D. A. Biesecker, Thursday, June 22, 2000, 8:30-10:00, 10:30-11:00am, Forum

## [13.01] The Absolute Abundance of Iron in the Solar Corona

S. M. White (University of Maryland), R. J. Thomas, J. W. Brosius (NASA/Goddard Space Flight Center), M. R. Kundu (University of Maryland)

We present a measurement of the abundance of Fe relative to H in the solar corona using a technique which differs from previous spectroscopic and solar wind measurements. Our method combines EUV line data from the CDS spectrometer on SOHO with thermal bremsstrahlung radio data from the VLA. The coronal Fe abundance is derived by equating the thermal bremsstrahlung radio emission calculated from the EUV Fe line data to that observed with the VLA, treating the Fe/H abundance as the sole unknown. We apply this technique to a compact cool active region and find Fe/H = 1.56 \times 10-4, or about 4 times its value in the solar photosphere. Uncertainties in the CDS radiometric calibration, the VLA intensity measurements, the atomic parameters, and the assumptions made in the spectral analysis yield net uncertainties of order 20%. This result implies that low first ionization potential elements such as Fe are enhanced in the solar corona relative to photospheric values.