Table 1.
Properties of the observed lines: wavelength (λ), transition, critical density (ncrit), upper level energy temperature (Eu/k), and Einstein coefficient (Aij). Numbers in parenthesis are power of 10. The critical densities have been calculated using the collisional rates with a) ortho-H2 (Offer et al. 1994), b) He (Hammami et al. 2008; Hammami et al. 2009), c) H2 (Yang et al. 2010), d) H0 (Launay & Roueff 1977), and e) para-H2 (Dubernet & Grosjean 2002; Phillips et al. 1996).
| λ [µm] | transition | ncrit [cm−3] | Eu/k [K] | Aij [s−1] | |
|---|---|---|---|---|---|
| OH | 84.6 | 2Π3/2 J=7/2−-5/2+ | 1 (10)a | 291 | 5.20 (-01) |
| OH | 119.4 | 2Π3/2 J=5/2+-3/2− | 1 (09)a | 120 | 1.38 (-01) |
| CH+ | 119.8 | J=3-2 | 4 (09)b | 240 | 2.20 (-01) |
| CH+ | 179.6 | J=2-1 | 6 (08)b | 120 | 6.10 (-02) |
| CH+ | 359.0 | J=1-0 | 7 (07)b | 40 | 6.36 (-03) |
| CO | 137.3 | J=19-18 | 5 (06)c | 1050 | 6.65 (-04) |
| 13CO | 227.1 | J=12-11 | 2 (06)c | 412 | 1.52 (-04) |
| C18O | 341.5 | J=8-7 | 6 (05)c | 190 | 4.47 (-05) |
| [CII] | 157.7 | 2P3/2-2P1/2 | 3 (03)d | 91 | 2.29 (-06) |
| [OI] | 145.5 | 3P0-3P1 | 2 (05)d | 327 | 1.66 (-05) |
| H2O | 269.3 | 111-000 | 1 (09)e | 53 | 1.84 (-02) |
| H2O | 398.7 | 211-200 | 3 (08)e | 137 | 7.05 (-03) |