The X - Ray Spectrum of a Planetary Nebula at High Resolution : Chandra Gratings Spectroscopy of BD + 30 ◦ 3639

We present the results of the first X-ray gratings spectroscopy observations of a planetary nebula (PN), the X-ray-bright, young BD+303639. We observed BD+303639 for a total of 300 ks with the Chandra X-ray Observatory’s Low Energy Transmission Gratings in combination with its Advanced CCD Imaging Spectrometer (LETG/ACIS-S). The LETG/ACIS-S spectrum of BD+303639 is dominated by H-like resonance lines of O viii and C vi and the He-like triplet line complexes of Ne ix and O vii. Other H-like resonance lines, such as N vii, as well as lines of highly ionized Fe, are weak or absent. Continuum emission is evident over the range 6–18 Å. Spectral modeling indicates the presence of a range of plasma temperatures from Tx ∼ 1.7 × 10 6 K to 2.9 × 10 K and an intervening absorbing column NH ∼ 2.4 × 10 21 cm. The same modeling conclusively demonstrates that C and Ne are highly enhanced, with abundance ratios of C/O ∼15–45 and Ne/O ∼3.3–5.0 (90% confidence ranges, relative to the solar ratios), while N and Fe are depleted, N/O ∼0.0–1.0 and Fe/O ∼0.1–0.4. The intrinsic luminosity of the X-ray source determined from the modeling and the measured flux (FX = 4.1× 10 −13 ergs cm s) is LX ∼ 8.6× 10 32 erg s (assuming D = 1.2 kpc). These gratings spectroscopy results are generally consistent with earlier results obtained from X-ray CCD imaging spectroscopy of BD+303639, but are