HII Case B Recombination Coefficients

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Alpha B HII.png

Recombination coefficients, Case B, HII -> HI

Contents

AAM

Derived from Seaton, MNRAS 119, 81 (1959)

\alpha^B_{HII} = 2.065\times 10^{-17} T^{-0.5} (5.62 - \mathrm{ln}T/2 + 8.68\times 10^{-3}T^{1/3} + 2.01\times 10^{-5}T^{0.8})\mathrm{m}^3 \mathrm{s}^{-1}

T < 105 K

HG97

Fit to Ferland92

\alpha^B_{HII} = 4.881\times 10^{-12} T^{-1.5} (1 + 114.8*T^{-0.407} )^{-2.242} \mathrm{m}^3 \mathrm{s}^{-1}

T < 109 K


Spitzer78

\alpha^B_{HII} = 2.066\times 10^{-17} T^{-1/2} \phi \mathrm{m}^3 \mathrm{s}^{-1}

T φ
31.3 3.89
62.5 3.57
125 3.25
250 2.92
500 2.60
1000 2.27
2000 1.96
4000 1.64
8000 1.34
16000 1.06
32000 0.80
64000 0.59

Ferland92

log(T) αB [m3 s-1]
0.5 5.758\times 10^{-17}
1.0 2.909\times 10^{-17}
1.5 1.440\times 10^{-17}
2.0 6.971\times 10^{-18}
2.5 3.282\times 10^{-18}
3.0 1.489\times 10^{-18}
3.5 6.430\times 10^{-19}
4.0 2.588\times 10^{-19}
4.5 9.456\times 10^{-20}
5.0 3.069\times 10^{-20}
5.5 8.793\times 10^{-21}
6.0 2.245\times 10^{-21}
6.5 5.190\times 10^{-22}
7.0 1.107\times 10^{-22}
7.5 2.221\times 10^{-23}
8.0 4.267\times 10^{-24}
8.5 7.960\times 10^{-25}
9.0 1.457\times 10^{-25}
9.5 2.636\times 10^{-26}
10 4.737\times 10^{-27}

Hummer94

Hummer 1994 MNRAS 268, 109

log(T) αB [10-17 m3 s-1]
1.0 9.283
1.2 8.823
1.4 8.361
1.6 7.898
1.8 7.435
2.0 6.973
2.2 6.512
2.4 6.054
2.6 5.599
2.8 5.147
3.0 4.700
3.2 4.258
3.4 3.823
3.6 3.397
3.8 2.983
4.0 2.584
4.2 2.204
4.4 1.847
4.6 1.520
4.8 1.226
5.0 0.9696
5.2 0.7514
5.4 0.5710
5.6 0.4257
5.8 0.3117
6.0 0.2244
6.2 0.1590
6.4 0.1110
6.6 0.07642
6.8 0.05199
7.0 0.03498

See also

Recombination Coefficients

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