The extreme-ultraviolet spectrum of the central star of the planetary nebula NGC 1360
Abstract
We have used the Extreme Ultraviolet Explorer (EUVE) to obtain the first EUV spectrum of the central star of a planetary nebula, that of NGC 1360. The photospheric spectrum shows continuum absorption edges due to O^4+ as well as absorption-line features. NLTE model atmospheres including line blanketing by iron-group elements can match the general level and shape of the spectrum, but are not capable of explaining all the observed features, precluding a detailed fit. Our solar abundance models require T_eff=110000K, logg=6.0 and N_H=8.5x10^19cm^-2. A new optical spectrum is presented and analysed with NLTE models. Stellar parameters in reasonable agreement with the EUV results are derived. It is found that many optical lines need to be considered, otherwise the best fits are not necessarily unique. This data set will provide a stern test for future NLTE models, which will need to include still more line blanketing before a totally satisfactory fit is obtained.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- December 1996
- DOI:
- 10.1093/mnras/283.3.830
- Bibcode:
- 1996MNRAS.283..830H
- Keywords:
-
- STARS: AGB AND POST-AGB;
- STARS: ATMOSPHERES;
- STARS: FUNDAMENTAL PARAMETERS;
- WHITE DWARFS;
- PLANETARY NEBULAE: INDIVIDUAL: NGC 1360;
- X-RAYS: STARS.