GT Observations of Active Cool Stars: AR Lac

GTAR Lac is a fully eclipsing RS CVn binary system with extremely active coronae on both stars. Previous missions have found a prominent Xray minimumaround the optical primary eclipse when the G star is occulted, and a shallowminimum around secondary eclipse. We propose here to study one ingress to or oneegress from the primary eclipse. We will use the EPIC cameras to obtain a lightcurve in unprecedented detail, the RGS combined with the EPICs to determinetimedependent emission measure distributions and abundances, and the RGS tosearch for time/heightdependent densities. Simultaneous optical and radioobservations will be proposed. One EPIC MOS will be operated in TIMING/mediumfilter mode, while the pn will observe with the SML window and thick filter. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]