LIU, XW;
BARLOW, MJ;
DANZIGER, IJ;
CLEGG, RES;
(1995)
Neutral carbon far-red forbidden line emission from planetary nubulae.
Monthly Notices of the Royal Astronomical Society
, 273
(1)
pp. 47-58.
10.1093/mnras/273.1.47.
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Abstract
The temperature-sensitive neutral carbon forbidden lines at 8727, 9824 and 9850 Å have been measured simultaneously for the first time from a planetary nebula. The nebulae NGC 2346, NGC 2440, NGC 3132 and IC 4406 were observed. Accurate rest wavelengths of these lines are obtained. The observed line ratios I(λ9824+λ9850)/I(λ8727) are consistent with collisional excitation by electron impacts. It is demonstrated that radiative recombination and stellar continuum fluorescence are unimportant in exciting the observed [CI] lines, with the possible exception of NGC 2440 where a contribution from the former process cannot be ruled out. For NGC 2346, NGC 3132 and IC 4406, the observed [C I]line ratios yield electron temperatures between 7400 and 8000 K, about 1800 to 2800 K lower than those deduced from the [N II], [S III] and [O III] line ratios that we also measured. Electron densities are derived from the observed [N I], [S II] and [Cl III] doublet ratios.
| Type: | Article |
|---|---|
| Title: | Neutral carbon far-red forbidden line emission from planetary nubulae |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/273.1.47 |
| Publisher version: | https://doi.org/10.1093/mnras/273.1.47 |
| 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. |
| Keywords: | line formation, planetary nebulae: general |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices 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.ucl.ac.uk/id/eprint/10096154 |
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