On the sizes of stellar X-ray coronae

  title={On the sizes of stellar X-ray coronae},
  author={J. Ness and M. Gudel and J. Schmitt and M. Audard and A. Telleschi},
  journal={Astronomy and Astrophysics},
Spatial information from stellar X-ray coronae cannot be assessed directly, but scaling laws from the solar corona make it possible to estimate sizes of stellar coronae from the physical parameters temperature and density. While coronal plasma temperatures have long been available, we concentrate on the newly available density measurements from line fluxes of X-ray lines measured for a large sample of stellar coronae with the Chandra and XMM-Newton gratings. We compiled a set of 64 grating… Expand
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Non-degenerate stars of essentially all spectral classes are soft X-ray sources. Their X-ray spectra have been important in constraining physical processes that heat plasma in stellar environments toExpand
We present evidence of Fe fluorescent emission in the Chandra HETGS spectrum of the single G-type giant HR 9024 during a large flare. In analogy to solar X-ray observations, we interpret the observedExpand
X-ray Diagnostics of Grain Depletion in Matter Accreting onto T Tauri Stars
Recent analysis of high-resolution Chandra X-ray spectra has shown that the Ne/O abundance ratio is remarkably constant in stellar coronae. Based on this result, we point out the utility of the Ne/OExpand
High-resolution X-ray spectroscopy of T Tauri stars in the Taurus-Auriga complex
Context. Di erences have been reported between the X-ray emission of accreting and non-accreting stars. Some observations have suggested that accretion shocks could be responsible for part of theExpand
X-rays from T Tauri: a test case for accreting T Tauri stars
Context. The generation of X-rays in accreting T Tauri stars (TTS) is thought to be predominantly due to energy dissipation in magnetic elds, but alternative X-ray generation mechanisms have beenExpand
X-ray emission processes in stars and their immediate environment
  • P. Testa
  • Physics, Medicine
  • Proceedings of the National Academy of Sciences
  • 2010
The progress made in the study of high energy stellar physics and its impact in a wider astrophysical context is discussed, focusing on the role of spectral diagnostics now accessible. Expand


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