High resolution X-ray spectroscopy of $\zeta$ Puppis with the XMM-Newton reflection grating spectrometer

By S. Kahn, M. Leutenegger, J. Cottam, G. Rauw, J. Vreux, A. D. Boggende, R. Mewe, M. Guedel. 2000

153 citations recorded by the source corpus.

We present the rst high resolution X-ray spectrum of the bright O4Ief supergiant star Puppis, obtained with the Reflection Grating Spectrometer on-board XMM-Newton. The spectrum exhibits bright emission lines of hydrogen-like and helium-like ions of nitrogen, oxygen, neon, magnesium, and silicon, as well as neon-like ions of iron. The lines are all signicantly resolved, with characteristic velocity widths of order 1000{1500 km s 1 . The nitrogen lines are especially strong, and indicate that the shocked gas in the wind is mixed with CNO-burned material, as has been previously inferred for the atmosphere of this star from ultraviolet spectra. We nd that the forbidden to intercombination line ratios within the helium-like triplets are anomalously low for N VI, O VII, and Ne IX. While this is sometimes indicative of high electron density, we show that in this case, it is instead caused by the intense ultraviolet radiation eld of the star. We use this interpretation to derive constraints on the location of the X-ray emitting shocks within the wind that are consistent with current theoretical models for this system.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/9b54de7bbed72ef93045e8879a69166dea94b566

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In Astronomy and Astrophysics

1. R. Townsend
2. S. Owocki
3. M. Oksala
4. A. ud-Doula
5. J. Macfarlane
6. D. Cohen
7. S. Tonnesen
8. M. Gagne

In Atomic and Molecular Physics, and Optics

1. R. Townsend
2. M. Gudel

Citations in the corpus

• Chandra HETGS Multiphase Spectroscopy of the Young Magnetic O Star θ1 Orionis C (2005, methodology): “This head-on collision between fast wind streams can lead to very high (T ≫ 107 K) shock temperatures, much higher than those seen in observations of normal O stars (e.g., ζ Pup; Hillier et al. 1993).”
• X-ray spectroscopy of stars (2009, background): “By estimating the emission measures (EMs) for each line (EM = 4πd2Fline/Emissivity(Te), with d being the distance andFline the line flux), Kahn et al (2001) further showed thatζ Pup displays a large overabundance in nitrogen and that onlya small fraction of the wind emits X-rays (since the measured…”