We present high-resolution X-ray spectra of the multiple (hierarchical quadruple) weak-lined T Tauri star system HD 98800, obtained with the High Energy Transmission Grating Spectrograph (HETGS) on board the Chandra X-Ray Observatory. In the zeroth-order Chandra/HETGS X-ray image, both principle binary components of HD 98800 (A and B, separation 0.8") are detected; component A was observed to flare during the observation. The infrared excess (dust disk) component, HD 98800B, is a factor of ~4 fainter in X-rays than the apparently “diskless” HD 98800A in quiescence. The line ratios of He-like species (e.g., Ne ix and O vii) in the HD 98800A spectrum indicate that the X-ray–emitting plasma around HD 98800 is in a typical coronal density regime (log n<~11 ). We conclude that the dominant X-ray–emitting component(s) of HD 98800 is (are) coronally active. The sharp spectral differences between HD 98800 and the classical T Tauri star TWHya demonstrate the potential utility of high-resolution X-ray spectroscopy in providing diagnostics of pre–main-sequence accretion processes (Refer to PDF file for exact formulas).
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Astrophys.J.L. 605 (2004) L49-L52
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