The Photospheric-to-Coronal Iron Abundance from X-ray Lines Observed by YOHKOH and Other Satellites

We have analyzed the intensities of photospherically formed K_alpha lines (1.936, 1.940A) and the Fe xxv resonance line (1.850A) observed by X-ray spectrometers on the P78-1 and S.M.M. spacecraft to deduce that the photospheric abundance of iron is not significantly different from the coronal abundance, despite recent suggestions that the coronal abundance is up to a factor of about three higher. This result confirms an earlier analysis of yohkoh data using the K_beta line and Fe xxv resonance line features.