X-Ray Line Emission from the Hot Stellar Wind of θ[TSUP]1[/TSUP] Orionis C

We present a first emission line analysis of a high resolution X-ray spectrumof the stellar wind of theta 1 Ori C obtained with the High Energy Transmissiongrating Spectrometer onboard the Chandra X-ray Observatory. The spectra areresolved into a large number of emission lines from H- and He-like O, Ne, Mg,Si, S, Ar and Fe ions. The He-like Fe XXV and Li-like Fe XXIV appear quitestrong indicating very hot emitting regions. From H/He flux ratios, as well asfrom Fe He/Li emission measure ratios we deduce temperatures ranging from 0.5to 6.1 x 10^7 K. The He-triplets are very sensitive to density as well. Atthese temperatures the relative strengths of the intercombination and forbiddenlines indicate electron densities well above 10^12 cm^-3. The lines appearsignificantly broadened from which we deduce a mean velocity of 770 km/s with aspread between 400 and 2000 km/s. Along with results of the deduced emissionmeasure we conclude that the X-ray emission could originate in dense and hotregions with a characteristic size of less then 4 x 10^10 cm.Comment: 4 pages, 3 figure