| Ion | R1 | R2 | R3 | R4 | G04a | PNeb | TI PNec | H IId | Sune |
| He/H |
|
|
|
|
|
|
|
|
|
| O /H |
|
|
|
|
|
|
|
|
|
| N /H |
|
|
|
|
|
|
|
|
|
| Ne/H |
|
|
- | - |
|
|
|
|
|
| Ar/H |
|
|
|
|
- |
|
|
|
|
| S /H |
|
|
|
|
|
|
|
|
|
|
a Taken from Górny et al. (2004). b Average for PNe (Kingsburgh & Barlow 1994). c Average for type I PNe (Kingsburgh & Barlow 1994). d Average for H II regions (Shaver et al. 1983). e The Sun (Grevesse et al. 2007). |