Two-Temperature X-Ray Emission from the Planetary Nebula NGC 7293 (original) (raw)
NASA/ADS
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Abstract
ROSAT Position Sensitive Proportional Counter (PSPC) observations of the planetary nebula NGC are reported here. This planetary nebula is here the first discovered to show clearly two components in its X-ray spectrum. A two-component model consisting of a blackbody and a Raymond-Smith thermal plasma is fitted to the observed ROSAT PSPC spectrum. This results in a temperature of T1 = 1.4 x 105 K for the blackbody component and a temperature T2 = 8.7 x 106 K for the hot plasma component, at a hydrogen column density NH = 1.4 x 1020/sq cm. The temperature of the blackbody component is consistent with the helium Zanstra temperature of the central star, indicating that it may be attributed to the photosphere of the central star. 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 bubble predicted by the interacting wind model. A lower limit of the electron density in the hot plasma is found to be approximately 10/cu cm.
Publication:
The Astrophysical Journal
Pub Date:
February 1994
DOI:
Bibcode:
Keywords:
- Black Body Radiation;
- High Temperature Plasmas;
- Nonthermal Radiation;
- Planetary Nebulae;
- Stellar Temperature;
- X Ray Astronomy;
- X Ray Spectra;
- Position Sensing;
- Proportional Counters;
- Rosat Mission;
- Spatial Resolution;
- Spectral Resolution;
- X Ray Telescopes;
- Astrophysics