Abstract
We show that there is a strong correlation between the temperature of the ionization source and the emission lines observed in PNe for a sample of the Large and Small Magellanic Clouds. We use the principal component analysis to build an indicator of temperature from the emission lines observed. Such indicator can be used to estimate the temperature of the central star in PNe of distant galaxies, where is possible to observe emission lines.
λ & Ion & a_λ
3869 & Ne III & 20.32
4363 & O III & 96.25
4648 & C III & 24.94
4686 & He II & 26.81
4713 & Ar IV & 245.97
4740 & Ar IV & 253.53
5412 & O I & 286.63
6300 & O I & 88.52
Using data from the literature we define an index I for the lines that correlate best with temperature
I = {1}/{N} ( sum_{i=1}^{n} a_{λ_{i}}F_{λ_{i}} + C )
where C=769.23, N=18000, and a_λ depends on the spectral line (see table above).}
