Table 2: Abundances.
Species $\mathcal{A}_i({\rm gas})$ $\delta_i$ $\mathcal{A}_i({\rm total})$
Hea,c $8.5 \times 10^{-2} $ 1.0 $8.5 \times 10^{-2} $
C $1.4 \times 10^{-4} $ 0.6 $2.5 \times 10^{-4} $
N $5.2 \times 10^{-5} $ 0.7 $7.2 \times 10^{-5} $
O $3.4 \times 10^{-4} $ 0.7 $4.7 \times 10^{-4} $
Si $1.7 \times 10^{-6} $ 0.05 $3.4 \times 10^{-5} $
S $6.9 \times 10^{-6} $ 0.5 $1.4 \times 10^{-5} $
Cl $5.4 \times 10^{-8} $ 0.2 $2.4 \times 10^{-7} $
Fe $2.0 \times 10^{-7} $ 0.007 $2.8 \times 10^{-5} $
Pb,c $3.9 \times 10^{-8} $ 0.1 $2.9 \times 10^{-7} $
Na $5.9 \times 10^{-7} $ 0.4 $1.5 \times 10^{-6} $
Mg $2.7 \times 10^{-7} $ 0.08 $3.4 \times 10^{-6} $
Nec     $6.9 \times 10^{-5} $
Al     $2.3 \times 10^{-6} $
Ar     $1.5 \times 10^{-6} $
Ca     $2.0 \times 10^{-6} $
Cr     $4.4 \times 10^{-7} $
Ni     $1.7 \times 10^{-6} $
Notes:
a Present in both PDR and XDR chemical network.
b Present in PDR chemical network.
c Used to calculate $\sigma_{\rm pa}$ for XDR.

Source LaTeX | All tables | In the text

Article Contents
1 Introduction
2 The photon dominated region model
3 PDR test models
4 The X-ray dominated region model
5 XDR test models
6 Conclusion
References
Online Material
Appendix A: Heating processes in PDRs
Appendix B: Heating processes in XDRs
Appendix C: Cooling processes
Appendix D: Chemistry
Appendix E: Energy deposition rate per hydrogen nucleus
List of tables
List of figures