Table 5: Plasma diagnostics.
ID Diagnostic Result

$T_{\rm e}$ (K)

1 [Ne III] 15 $\mu$ m/( $\lambda3868+\lambda3967$ ) 12 900

2 [Ar III] $\lambda$ 7135/ $\lambda$ 5192 12 800

3 [O III] ( $\lambda4959+\lambda5007$ )/ $\lambda$ 4363 12 600

4 [N II] ( $\lambda6548+\lambda6584$ )/ $\lambda$ 5754 12 900

5 [Ne IV] $\lambda$ 1602/( $\lambda2422+\lambda2425$ ) 15 300

6 [O III] $\lambda$ 4363/ $\lambda$ 1663 14 700

7 [O II] ( $\lambda7320+\lambda7330$ )/ $\lambda$ 3726 18 700

8 [O I] $\lambda$ 5577/( $\lambda6300+\lambda6363$ ) 10 400

9 [Mg V] $\lambda$ 2783/5.6 $\mu$ m 15 600

He I $\lambda 6678/\lambda 4471$ 9430

He I $\lambda 6678/\lambda 5876$ 12 700

He I $\lambda 7281/\lambda 5876$ 8800

He I $\lambda 7281/\lambda 6678$ 10 530

BJ/H 11 12 800

$\log N_{\rm e}$ (cm^-3)

10 [Ar IV] $\lambda$ 4740/ $\lambda$ 4711 4.77

11 [C III] $\lambda$ 1906/ $\lambda$ 1909 4.80

12 [Cl III] $\lambda$ 5537/ $\lambda$ 5517 4.70

13 [Ne IV] $\lambda$ 2425/ $\lambda$ 2423 4.69

14 [Si III] $\lambda$ 1884/ $\lambda$ 1892 4.54

15 [S II] $\lambda$ 6731/ $\lambda$ 6716 $\ga$ 5

16 [Ne V] 24 $\mu$ m/14 $\mu$ m 4.31

17 [Ne III] 15 $\mu$ m/36 $\mu$ m 4.89

18 [O II] $\lambda$ 3726/ $\lambda$ 3729 4.68

19 [Fe III] $\lambda$ 4881/ $\lambda$ 4701 5.27

20 [Fe III] $\lambda$ 4701/ $\lambda$ 4733 4.50

21 [Fe III] $\lambda$ 4733/ $\lambda$ 4754 4.27

H I Balmer decrement $\sim$ 5

He II Pfund decrement $\sim$ 5

**Table 5:** Plasma diagnostics.
ID	Diagnostic	Result
		$T_{\rm e}$ (K)
1	[Ne III] 15 $\mu$ m/( $\lambda3868+\lambda3967$ )	12 900
2	[Ar III] $\lambda$ 7135/ $\lambda$ 5192	12 800
3	[O III] ( $\lambda4959+\lambda5007$ )/ $\lambda$ 4363	12 600
4	[N II] ( $\lambda6548+\lambda6584$ )/ $\lambda$ 5754	12 900
5	[Ne IV] $\lambda$ 1602/( $\lambda2422+\lambda2425$ )	15 300
6	[O III] $\lambda$ 4363/ $\lambda$ 1663	14 700
7	[O II] ( $\lambda7320+\lambda7330$ )/ $\lambda$ 3726	18 700
8	[O I] $\lambda$ 5577/( $\lambda6300+\lambda6363$ )	10 400
9	[Mg V] $\lambda$ 2783/5.6 $\mu$ m	15 600
	He I $\lambda 6678/\lambda 4471$	9430
	He I $\lambda 6678/\lambda 5876$	12 700
	He I $\lambda 7281/\lambda 5876$	8800
	He I $\lambda 7281/\lambda 6678$	10 530
	BJ/H 11	12 800
		$\log N_{\rm e}$ (cm^-3)
10	[Ar IV] $\lambda$ 4740/ $\lambda$ 4711	4.77
11	[C III] $\lambda$ 1906/ $\lambda$ 1909	4.80
12	[Cl III] $\lambda$ 5537/ $\lambda$ 5517	4.70
13	[Ne IV] $\lambda$ 2425/ $\lambda$ 2423	4.69
14	[Si III] $\lambda$ 1884/ $\lambda$ 1892	4.54
15	[S II] $\lambda$ 6731/ $\lambda$ 6716	$\ga$ 5
16	[Ne V] 24 $\mu$ m/14 $\mu$ m	4.31
17	[Ne III] 15 $\mu$ m/36 $\mu$ m	4.89
18	[O II] $\lambda$ 3726/ $\lambda$ 3729	4.68
19	[Fe III] $\lambda$ 4881/ $\lambda$ 4701	5.27
20	[Fe III] $\lambda$ 4701/ $\lambda$ 4733	4.50
21	[Fe III] $\lambda$ 4733/ $\lambda$ 4754	4.27
	H I Balmer decrement	$\sim$ 5
	He II Pfund decrement	$\sim$ 5

Source LaTeX | All tables | In the text

	1 Introduction
	2 Observations
	3 Raman scattering features
	4 Reddening summary
	5 Physical conditions
	6 Elemental abundances
	7 The central star
	8 Summary
	References
	Online Material
	Appendix A: Emission from heavy elements (Z>30)
	Appendix B: Atomic data references