2015A&A...574A...1G

We present an analysis of XMM-Newton Reflection Grating Spectrometer (RGS) observations of the planetary nebula (PN) NGC6543. These observations render it the second PN with high-resolution X-ray spectroscopic observations after BD+30°3639. The observations consist of 26 pointings, 14 of which included RGS observations for a total integration time of 435ks. Many of these observations, however, were severely affected by high-background levels, and the net useful exposure time is drastically reduced to 25ks. Only the OVII triplet at 22Å is unambiguously detected in the RGS spectrum of NGC6543. We find this spectrum consistent with an optically thin plasma at 0.147keV (1.7MK) and nebular abundances. Unlike BD+30 3639, the X-ray emission from NGC6543 does not reveal overabundances of C and Ne. The results suggest that the N/O ratio of the hot plasma is consistent with that of the stellar wind, that is, it is lower than the nebular N/O ratio, but this result is not conclusive.