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We present the results of the first X-ray gratings spectroscopy observationsof a planetary nebula (PN), the X-ray-bright, young BD+30 3639. We observedBD+30 3639 for a total of 300 ks with the Chandra X-ray Observatory's LowEnergy Transmission Gratings in combination with its Advanced CCD ImagingSpectrometer(LETG/ACIS-S). The LETG/ACIS-S spectrum of BD+30 3639 is dominatedby H-like resonance lines of O viii and C sc vi and the He-like triplet linecomplexes of Ne ix and O vii. Other H-like resonance lines, such as N vii, aswell as lines of highly ionized Fe, are weak or absent. Continuum emission isevident over the range 6-18 A. Spectral modeling indicates the presence of arange of plasma temperatures from T~1.7x10^6 K to 2.9x10^6 K and an interveningabsorbing column N_H~2.4x10^21 cm-2. The same modeling conclusivelydemonstrates that C and Ne are highly enhanced, with abundance ratios ofC/O~15-45 and Ne/O~3.3-5.0 (90% confidence ranges, relative to the solarratios), while N and Fe are depleted, N/O~0.0-1.0 and Fe/O~0.1-0.4. Theintrinsic luminosity of the X-ray source determined from the modeling and themeasured flux (F_X = 4.1x10^-13 ergs cm-2 s-1) is L_X~8.6x10^32 ergs-1(assuming D = 1.2kpc). These gratings spectroscopy results are generallyconsistent with earlier results obtained from X-ray CCD imaging spectroscopy ofBD+30 3639, but are far more precise. The tight constraints placed on the(nonsolar) abundances directly implicate the present-day central star -- hence,ultimately, the intershell region of the progenitor asymptotic giant branchstar -- as the origin of the shocked plasma now emitting in X-rays.

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