XMM-Newton observations of zeta Orionis (O9.7 Ib): A collisional ionization equilibrium model

  title={XMM-Newton observations of zeta Orionis (O9.7 Ib): A collisional ionization equilibrium model},
  author={A. J. J. Raassen and K. van der Hucht and Neil A. Miller and Joseph Patrick Cassinelli},
  journal={Astronomy and Astrophysics},
We present XMM-Newton observations of the O supergiant zeta Orionis (O9.7 Ib). The spectra are rich in emission lines over a wide range of ionization stages. The RGS spectra show for the first time lines of low ion stages such as C VI, N VI, N VII, and O VII. The line profiles are symmetric and rather broad (FWHM approximate to 1500 km s(-1)) and show only a slight blue shift. With the XMM-EPIC spectrometer several high ions are detected in this star for the first time including Ar XVII and S… 

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