We present the results of the first X-ray gratings spectroscopy observations of a planetary nebula (PN), the X-ray-bright, young BD+30 3639. We observed BD+30 3639 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+30 3639 is dominated by H-like resonance lines of O viii and C sc 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 A. Spectral modeling indicates the presence of a range of plasma temperatures from T~1.7x10^6 K to 2.9x10^6 K and an intervening absorbing column N_H~2.4x10^21 cm-2. 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 (F_X = 4.1x10^-13 ergs cm-2 s-1) is L_X~8.6x10^32 erg s-1(assuming D = 1.2kpc). These gratings spectroscopy results are generally consistent with earlier results obtained from X-ray CCD imaging spectroscopy of BD+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 branch star -- as the origin of the shocked plasma now emitting in X-rays.

Publication Date



Also archived in: arXiv:0806.2281v2 [astro-ph]Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type


Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)


RIT – Main Campus