Table 1
Summary of the molecular emission lines.
| Transition | ν (GHz) | log10AE | EU/kB (K) | nc(20 K) (cm−3) | nc(100 K) (cm−3) |
|---|---|---|---|---|---|
| SiO 5–4 | 217.104980 | −3.284 | 31.3 | 9.8 × 105 | 7.2 × 105 |
| DCNa 3–2 | 217.238538 | −3.340 | 20.9 | 5.5 × 106 | 2.1 × 106 |
| H2CO 30,3−20,2 | 218.222192 | −3.550 | 21.0 | 7.8 × 105 | 4.7 × 105 |
| CH3OCHO 173,14−163,13 E | 218.280900 | −3.822 | 99.7 | _b | _b |
| HCCCN 24–23 | 218.324723 | −3.083 | 131.0 | 1.3 × 106 | 7.7 × 105 |
| CH3OH 42,3−31,2 | 218.440063 | −4.329 | 45.5 | 1.3 × 105 | 8.8 × 104 |
| H2CO 32,1−22,0 | 218.760066 | −3.802 | 68.1 | 3.1 × 105 | 2.4 × 105 |
| SO 65–54 | 219.949442 | −3.874 | 35.0 | 4.6×105c | 3.4 × 105 |
| CH3CN 121−111 | 220.743011 | −3.199 | 76.0 | 2.0 × 106 | 8.7 × 105 |
| CH3CN 120−110 | 220.747261 | −3.196 | 68.9 | 2.0 × 106 | 8.7 × 105 |
Notes. Col. 1: transition. Col. 2: rest frequency v. Col. 3: Einstein’s coefficient AE. Col. 4: energy of the upper level EU/kB in units of K. Col. 5: critical density nc calculated at the temperature of 20 K. Col. 6: critical density nc calculated at the temperature of 100 K. The critical densities have been calculated from Eq. (4) of Shirley (2015) using the collisional coefficients Cij from Leiden Atomic and Molecular Database. (a)Collisional coefficient for DCN not available; thus, we used the collisional coefficients of HCN; (b)No collisional coefficient found for the CH3OCHO E-state; (c)Extrapolated from the values at 100 K, 80 K, and 60 K since collisional coefficients were not available for T=20 K.
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