  The Chandra X-ray Observatory grating spectrometers allow study of stellar
spectra at resolutions on the order of 1000. Prior x-ray observatories' low
resolution data have shown that nearly all classes of stars emit x-rays.
Chandra reveals details of line and continuum contributions to the spectra
which can be interpreted through application of plasma models based on atomic
databases. For cool stars with hot coronae interpreted in the Solar paradigm,
assumption of collisional ionization equilibrium allows derivation of
temperature distributions and elemental abundances. Densities can be derived
from He-like ion's metastable transition lines. Abundance trends are unlike the
Sun, as are the very hot temperature distributions. For young stars, there is
evidence of accretion driven x-ray emission, rather than magnetically confined
plasma emission. For some hot stars, the expected emission mechanism of shocked
winds has been challenged; there is now evidence for magnetically confined
thermal plasmas. The helium-like line emission in hot stars is susceptible to
photoexcitation, which can also be exploited to derive wind structure.

Astrophysics