Evidence for Accretion in the High-Resolution X-Ray Spectrum of the T Tauri Star System Hen 3-600

David P. Huenemoerder, Massachusetts Institute of Technology
Joel H. Kastner, Rochester Institute of Technology
Paola Testa, Massachusetts Institute of Technology
Norbert S. Schulz, Massachusetts 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: https://doi.org/10.1086/522921

© 2007 The American Astronomical Society

Also archived in: arXiv:0708.4393v1 [astro-ph]

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 T Tauri star system Hen 3-600, obtained with the High Energy Transmission Grating Spectrograph on the Chandra X-ray Observatory. Two binary components were detected in the zeroth-order image. Hen 3-600-A, which has a large mid-infrared excess, is a 2-3 times fainter in X-rays than Hen 3-600-B, due to a large flare on B. The dispersed X-ray spectra of the two primary components overlap spatially; spectral analysis was performed on the combined system. Analysis of the individual spectra was limited to regions where the contributions of A and B can be disentangled. This analysis results in two lines of evidence indicating that the X-ray emission from Hen 3-600 is derived from accretion processes: line ratios of O VII indicate that the characteristic density of its X-ray-emitting plasma is large; a significant component of low-temperature plasma is present and is stronger in component A. These results are consistent with results obtained from X-ray gratings spectroscopy of more rapidly accreting systems. All of the signatures of Hen 3-600 that are potential diagnostics of accretion activity -- X-ray emission, UV excess, H-alpha emission, and weak infrared excess -- suggest that its components represent a transition phase between rapidly accreting, classical T Tauri stars and non-accreting, weak-lined T Tauri stars.