Characterization of X-ray emission from T Tauri stars

Sonali J. Shukla (Vanderbilt University) , David Weintraub (Vanderbilt University), Joel Kastner (Rochester Institute of Technology), David Huenemoerder (MIT), Norbert Schulz (MIT), Paola Testa (MIT)

Although young stellar objects are known to be luminous and variable X-ray sources, the generation mechanism(s) of their X-rays are still unresolved. We have identified a sample of stars in the Chandra archives for which Chandra ACIS-S/HETGS long integration, high spectral resolution data exists. Our sample consists of both classical, weak-lined, and post-T Tauri stars as well as a young main sequence star. We are analyzing this data in a globally-consistent way to determine physical characteristics of the X-ray emitting plasma including temperature, density, and elemental abundances for each star. In addition, we are looking to confirm the results of recent studies that have shown that T Tauri stars have well-correlated H-alpha equivalent widths and f/i line ratios in He-like ions. Line density diagnostics have also shown that low-densities are associated with cool plasmas indicative of accretion shocks. Combining these diagnostic techniques for the variety of stars in our sample will enable us to identify similarities and differences among those stars that are thought to be actively accreting material from their circumstellar regions and those that have little or no accretion signatures in other wavelength regimes. We report on the first phase of our analysis of this sample of stars.