Table 4: Empirical abundance ratios of various elements, with the ICFs specified.
Ratio Value ICF

Our work

He/H $(8.96\pm0.42)\times10^{-2}$ He=He⁺+He⁺⁺

O/H $(1.45\pm0.27)\times10^{-4}$ O=O⁺+O⁺⁺

N/O $(4.12\pm0.95)\times10^{-2}$ N/O=N⁺/O⁺

Ne/O $(2.57\pm0.14)\times10^{-1}$ Ne/O=Ne⁺⁺/O⁺⁺

Vílchez et al. (1988)

He/H $8.3\times10^{-2}$

O/H $(2.0\pm0.3)\times10^{-4}$

N/O $(3.0\pm0.5)\times10^{-2}$

Ne/O $(2.5\pm0.5)\times10^{-1}$

**Table 4:** Empirical abundance ratios of various elements, with the ICFs specified.
Ratio	Value	ICF
Our work
He/H	$(8.96\pm0.42)\times10^{-2}$	He=He⁺+He⁺⁺
O/H	$(1.45\pm0.27)\times10^{-4}$	O=O⁺+O⁺⁺
N/O	$(4.12\pm0.95)\times10^{-2}$	N/O=N⁺/O⁺
Ne/O	$(2.57\pm0.14)\times10^{-1}$	Ne/O=Ne⁺⁺/O⁺⁺
Vílchez et al. (1988)
He/H	$8.3\times10^{-2}$
O/H	$(2.0\pm0.3)\times10^{-4}$
N/O	$(3.0\pm0.5)\times10^{-2}$
Ne/O	$(2.5\pm0.5)\times10^{-1}$

Source LaTeX | All tables | In the text

	1 Introduction
	2 Observational data and reduction
	3 Empirical diagnostics
	4 General strategy for model fitting
	5 Simple models
	6 Models with constrained density distribution
	7 Further refining of the models
	8 Sources of energy other than the ionizing flux
	9 Uncertainties in O/H and Ne/O
	10 Conclusion
	References
	Online Material
	Appendix A: Correction of Balmer lines used for dereddening
	Appendix B: Setting the geometric corrections A, B, and K