Chandra HETGS Multi-Phase Spectroscopy of the Young Magnetic O Star theta^1 Orionis C

Marc Gagne, Mary E. Oksala, David H. Cohen, Stephanie K. Tonnesen, Asif ud-Doula, Stanley P. Owocki, Richard H. D. Townsend, Joseph J. MacFarlane

West Chester University, University of Delaware, Swarthmore College, Columbia University, North Carolina State University, University of Delaware, University of Delaware, Prism Computational Sciences

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 .

Reference: ApJ, 628, in press
Status: Manuscript has been accepted


Comments: 52 pages, 14 figures (2 color), 6 tables