Cool Stars 14 - Submitted Abstract # 215 This version created on 05 October 2006 High-resolution X-ray Spectroscopy of the Nearby T Tauri Star System Hen 3-600 Joel Kastner, Rochester Institute of Technology David Huenemoerder, MIT Paola Testa, MIT Norbert Schulz, MIT David Weintraub, Vanderbilt University We present Chandra High Energy Transmission Gratings (HETG) spectroscopy of the multiple T Tauri star system Hen 3-600. Hen 3-600 is a member of the nearby (D ~ 50 pc) TW Hya Association (TWA), and is the third TWA member (after TW Hya itself and HD 98800) to be observed by Chandra/HETG. The two principle (M3) binary components of Hen 3-600 are separated by 1.4'' and are marginally to well resolved in the HETG data. The X-ray flux of component Hen 3-600A, which displays a mid-infrared excess indicative of the presence of a dusty circumstellar disk, is a factor ~2-3 smaller than that of Hen 3-600B. This difference is likely the result of a large flare at Hen 3-600B during our observation. We discuss the various plasma temperature and density diagnostics available in the high-resolution spectra of Hen 3-600A, Hen 3-600B, and the combined system, and compare these results with those previously obtained for TW Hya, HD 98800, and a handful of other pre-main sequence systems. As in other, key respects (e.g., UV excess, H-alpha line intensities), the individual and composite X-ray line spectra of Hen 3-600 indicate that its components (Hen 3-600A in particular) are transition objects, with emission signatures that lie between those of rapidly accreting, classical T Tauri stars (e.g., TW Hya and BP Tau) and those of apparently nonaccreting, weak-lined T Tauri systems (e.g., HD 98800 and AU Mic). ----------------------------------