Analysis (2)
With the nebular parameters established, we can now make
photoionization models and obtain nebular
abundances.
The data was fit with CLOUDY against the following lines:
| [Ne V] 3346 |
32 +/- 8 |
| [Ne V] 3426 |
86 +/- 9 |
| [Ne III] 3868 |
15 +/- 7 |
| H epsilon |
4 +/- 1 |
| H delta |
17 +/-2 |
| H gamma |
39 +/- 3 |
| He II 4686 |
77 +/-3 |
| H beta |
100 |
| [O III] 5007 |
3 +/- 1 |
| He II 5412 |
5 +/- 1 |
| H alpha |
281 +/- 10 |
The models are non-unique,
and many of the common coolant lines of PN are
unknown (we only have upper
limits).
We find the following:
-
The Oxygen abundance is well below
solar (105 - 500 times), depending on the electron temperature
of nebula (which will be higher than average in this object), and the abundances
of non-detected elements.
-
The Ne/O ratio seems abnormally high: 4.3
(compared to 0.26 for Galactic PN). This will need further verification,
as the lines are very faint. An intriguing possibility is that the
Oxygen was converted in Neon proposed by Howard
et al. (1997) for the abnormal halo PN BoBn1
(Ne/O = 0.8). This will need further study.
The Future:
- Our collaborators have been approved for HST STIS time
to obtain UV spectra. This will
allow us to obtain Carbon and Nitrogen abundances,
and better constrain
the nebular models.
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