Table 3
Disk-averaged column density and abundance of H2CO in HD 163296 and TW Hya.
| Object | Line | ∫ Iνdν | Eu | log(Aul) | ncrit | Navg | H2CO∕H2 |  |
|---|---|---|---|---|---|---|---|---|
| (mJy km s−1) | (K) | (s−1) | (cm−3) | (cm−2) | ||||
| HD 163296 | H2CO 312–211 | 890 ± 89 | 33.4 | − 3.55 | 5.7(06) | 2.1(12) | 6.3(−12) | <0.24 |
| TW Hya | H2CO 312–211 | 291 ± 29 | 33.4 | − 3.55 | 5.7(06) | 3.7(12) | 8.9(−13) | 1.27 ± 0.13 |
Notes. The disk-averaged column density was calculated using Eq. (1) with Tex = 25 K. The format a(b) translates to a × 10b. Flux errors are dominated by systematic uncertainties, taken to be 10%. (a) Ratios are determined using the CH3 OH disk-integrated column density from Table 2. HD 163296: based on the strictest upper limit from the CH3 OH 211 –202 (A) line. TW Hya: based on the stacked CH3OH detection. References.Wiesenfeld & Faure (2013); Qi et al. (2013); Öberg et al. (2017).
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