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N.S. Schulz, D.P. Huenemoerder (MIT), J.H. Kastner (RIT), C.R. Canizares (MIT)
Many highly resolved X-ray spectra of very young stars have become available through recent years and their analysis so far revealed a rather broad palette of plasma emissions. The study of high energy signatures from very young massive stars has always been difficult due to the short time scales involved in their evolution. The time between collapse, full hydrogen burning and disk dispersal in massive stars is of the order of 105 yr, in contrast to a few 106 yr for T Tauri stars. The high spatial and spectral resolution of Chandra made it possible to resolve the cores of very young open clusters in X-ray wavelengths. here we find that clusters as young as the Orion Nebula Cluster (~ 0.3 Myr) exhibit likely signatures of magnetic activity. Leading models favor a mechanims of a magnetically confined wind. Likely more evolved stars, for example in cores of clusters older than 3 Myr as in IC 1396 or NGC 2362, already behave more like the prototype O-star \zeta Pup. In contrast, high resolution X-ray spectra of low-mass T Tauri stars do not unanimously exhibit coronal signatures as expected, but in some cases emissions seem to be more compatible with accretion shocks. In this light and with findings from observations of stars with active coronae we provide new insights from high resolution X-ray spectroscopy of massive stars at possibly various evolutionary stages and compare them to spectral signatures from T Tauri stars at various evolutionary stages.
The author(s) of this abstract have provided an email address for comments about the abstract: nss@space.mit.edu
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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.