2-TEMPERATURE X-RAY-EMISSION FROM THE PLANETARY-NEBULA NGC-7293

ROSAT PSPC observations of the planetary nebula NGC are reported here. This planetary nebula is here the first discovered to show clearly tw o components in its X-ray spectrum. A two-component model consisting o f a blackbody and a Raymond-Smith thermal plasma is fitted to the obse rved ROSAT PSPC spectrum. This results in a temperature of T-1 = 1.4 x 10(5) K for the blackbody component and a temperature T-2 = 8.7 x 10( 6) K for the hot plasma component, at a hydrogen column density N-H, = 1.4 x 10(20) cm(-2). The temperature of the blackbody component is co nsistent with the helium Zanstra temperature of the central star, indi cating that it may be attributed to the photosphere of the central sta r. The high-temperature component is possibly from a corona around the central star, which may be related to a strong convection in the star . An alternative explanation is that the hot plasma resides in a hot b ubble predicted by the interacting wind model. A lower limit of the el ectron density in the hot plasma is found to be similar to 10 cm(-3).