The analysis of emission-line spectra from photoionized gas nebulae provides the best method to determine their chemical abundances. If we focus our attention on planetary nebulae (PNe) and HII regions, the abundance analysis will return the ISM chemistry of a given galaxy, in the past (Gyr ago) and in the present-time, respectively. Moreover, the utility of these results is based on the fact that altogether they provide important constraints to reconstruct the chemical evolution of the galaxy. Thus, the latter issue ultimately aim at a more complete understanding of the interplay of the different stellar populations in the galaxy's history as a whole. However, there are important uncertainties on the empirical determination of the nebular total chemical abundances, which rely on the ionization correction factors (ICF) method. Situation can be improved when, in addition of using only the optical wavelength spectral range, the near-IR spectrum is also available. Currently such a wavelength coverage is possible for a significant number of objects, indeed. In this contribution, we will present the updated corrections to the ICF method. The new set of equations was meant to be able to account for the non-spherical shapes of most PNe, subject on which we have been working the latest years. The potential use of these equations, with and without near-IR data, are discussed.
Asymmetrical Planetary Nebulae VI Conference
- Pub Date:
- April 2014
- stars: planetary nebulae;
- planetary nebulae: general