RGS Observations of the Two X-Ray-Brightest Planetary Nebulae: Origin of Hot Gas

Planetary nebulae (PNe) consist of material ejected by stars with masses lessthan 810 solar masses. The current fast stellar wind sweeps up the previousslow AGB wind to form the PN shell, and the shell interior is expected to befilled with hot gas that emits Xrays. Chandra and XMMNewton have detecteddiffuse Xrays from PNe at levels much lower than theoretical expectations. Thedifferent abundances of the fast stellar wind and the slow AGB wind traces theorigin of the hot gas in PNe. We request XMMNewton RGS observations of the twoXraybrightest PNe, BD+30 3639 and NGC 6543, to determine the chemicalabundances and origin of the hot gas and further use these to constrain theamount of heat conduction between the hot gas and the cool nebular shell. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]