The Coronal X-Ray Spectrum of the Multiple Weak-Lined T Tauri Star System HD 98800

Joel H. Kastner, Rochester Institute of Technology
David Huenemoerder, Massachusetts Institute for Technology Center for Space Research
Norbert Schulz, Massachusetts Institute for Technology Center for Space Research
Claude R. Canizares, Massachusetts Institute for Technology Center for Space Research
Jingqiang Li, Rochester Institute of Technology
David A. Weintraub, Vanderbilt University

This is the pre-print of an article published by the American Astronomical Society. The final, published version is available here:

© 2004 The American Astronomical Society.

Also archived in: arXiv: astro-ph/0403062 v1 2 Mar 2004

Support for this research was provided by contracts SV3-73016 (Chandra) and NAS8-01129 (HETG) to MIT.

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.


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).