NGC 6302: ionized by a very hot star or by a wind?

Lines of very highly ionized silicon recently discovered in the type I planetary nebula NGC 6302 implied a central star temperature of 450,000 K assuming that the high ionization lines were the result of photoionization. This is the highest central star temperature ever reported for a planetary nebula, and the effects of a luminous soft X-ray source on a surrounding nebula have never been examined. New photoionization model calculations assuming a very hot (T-asterisk = 450,000 K) central star are presented. Model calculations which show that such a high central star temperature can reproduce the observed global spectrum of NGC 6302 do not work well in detail. It seems more likely that the very high ionization lines are the result of shock ionization produced by strong winds from the central star. Both the level of ionization and the energetics are consistent with such an origin. Thus the ionization of this nebula may be the result of both collisional (the high-ionization lines) and photoionization (the traditional nebular lines). 21 refs.