Table 5.
Similarities between NGC 6781 and NGC 6720
| PNe | ε(He) | ε(CRL) | ε(CCEL) | ε(N) | ε(ORL) | ε(OCEL) | ε(Ne) | ε(S) | ε(Cl) | ε(Ar) | Teff (kK) | log g (cm s−2) | References |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NGC 6781 | 11.06 | 9.61 | 8.56–9.00 | 8.15 | … | 8.76 | 8.15 | 6.91 | 5.16 | 6.49 | 80–123 | 6.0–7.0 | 1, 2, 3, 4 |
| NGC 6720 | 11.05 | 9.10 | 8.59 | 8.22 | 9.18 | 8.80 | 8.23 | 6.86 | 5.19 | 6.54 | 80–135 | 6.9–7.0 | 5, 6, 7 |
References.
1
This work for abundances (see Section 3.1.3);
2
Schwarz & Monteiro 2006, for Teff and log g via photoionization modeling;
3
Rauch et al. 2004, for Teff and log g via stellar absorption fitting;
4
Liu et al. 2004a, for abundances;
5
McCarthy et al. 1997, for Teff and log g via stellar absorption fitting;
6
Napiwotzki 1999, for Teff and log g via stellar absorption fitting;
7
van Hoof et al. 2010, for Teff via Cloudy photoionization modeling.