Chandra HETGS Multi-Phase Spectroscopy of the Young Magnetic O Star   theta^1 Orionis C
  We report on four Chandra grating observations of the oblique magnetic rotator theta^1 Ori C (O5.5 V) covering a wide range of viewing angles with respect to the star's 1060 G dipole magnetic field. We employ line-width and centroid analyses to study the dynamics of the X-ray emitting plasma in the circumstellar environment, as well as line-ratio diagnostics to constrain the spatial location, and global spectral modeling to constrain the temperature distribution and abundances of the very hot plasma. We investigate these diagnostics as a function of viewing angle and analyze them in conjunction with new MHD simulations of the magnetically channeled wind shock mechanism on theta^1 Ori C. This model fits all the data surprisingly well, predicting the temperature, luminosity, and occultation of the X-ray emitting plasma with rotation phase. 
Marc Gagne, Mary E. Oksala, David H. Cohen, Stephanie K. Tonnesen,   Asif ud-Doula, Stanley P. Owocki, Richard H. D. Townsen...