DeMarco, O;
Barlow, MJ;
Storey, PJ;
(1997)
The WC10 central stars CPD-56 degrees 8032 and He 2-113 .1. Distances and nebular parameters.
Monthly Notices of the Royal Astronomical Society
, 292
(1)
pp. 86-104.
10.1093/mnras/292.1.86.
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Abstract
We present the results of an analysis of the WC10 central stars CPD −56°8032 and He 2-113 and of their surrounding planetary nebulae (PNe). UCL Echelle Spectrograph spectra with a resolving power of R = 50 000, covering the wavelength range 3600–9500 Å, were obtained for both objects. Expansion and radial velocities are derived from the nebular Balmer lines. Reddenings were derived from the observed Hα/Hβ decrements, as well as from the ratio of the radio free-free and Hβ fluxes. We find that E(B—V) = 0.68 for CPD−56°8032 and 1.00 for He 2-113. The bolometric luminosity is found to be 2820 D2 (kpc) L⊙ for CPD — 56°8032 and 2290 D2 (kpc) L⊙ for He 2-113. We have used a calibration based on Magellanic Cloud Wolf-Rayet central stars to estimate a distance of 1.35 kpc to CPD — 56°8032 and 1.50 kpc to He 2-113. A comparison of the radial velocities of interstellar Na I D-line absorption components with Galactic rotation curve predictions for each line of sight yields distances which agree within the uncertainties with these values. We also present deconvolved pre-COSTAR HST Hβ images, from which we derive nebular angular sizes of 1.6 × 2.1 arcsec2 for CPD—56°8032 and 1.4 × 1.1 arcsec2 for He 2-113. From our spectra, nebular electron temperatures of 8800 and 8400 K are derived for CPD. 56°8032 and He 2-113 respectively, while an electron density of 6 × 104 cm−3 is determined for both nebulae. Sulphur is found to have a near-solar abundance in both nebulae, and the nebular nitrogen abundances are also close to solar. The nebular C/O abundance ratios (determined with the help of low-resolution IUE spectra) are found to be equal to 13 for CPD. 56°8032 and 10 for He 2-113, respectively, significantly higher than the values normally found for Galactic PNe. We find no detectable amounts of hydrogen in either stellar wind.
| Type: | Article |
|---|---|
| Title: | The WC10 central stars CPD-56 degrees 8032 and He 2-113 .1. Distances and nebular parameters |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/292.1.86 |
| Publisher version: | https://doi.org/10.1093/mnras/292.1.86 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10096093 |
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