Acis/hetg Spectroscopy of the Active Binaries Algol & UX Ari

Previous low- and moderate-resolution X-ray spectroscopy of active binary stars have yielded surprising results concerning the abundances of the elements in these coronal plasmas, viz., that, in almost every well-studied case, a solar photospheric abundance plasma model cannot fit the observed spectrum: e.g., in some stars, Fe abundances of 10% of the solar value have been inferred. To verify and extend these findings, we propose to observe with the HETG two of the best-studied such stars, Algol and UX Ari. We will study the detailed structure of the He-like multiplets of the abundant elements O, Ne, Mg, Si, S, Ar, Ca, and Fe, and rederive their abundances, and also search for anomalous line ratios due to effects such as high resonance-line opacity and/or high electron densities.