Table 2
Disk-averaged column density and abundance of CH3OH in HD 163296 and TW Hya.
| Object | Line |  |
Eu | log(Aul) | ncrit | Navg | CH3OH∕H2 |
|---|---|---|---|---|---|---|---|
| (mJy km s−1) | (K) | (s−1) | (cm−3) | (cm−2) | |||
| HD 163296 | CH3OH 505–404 (E) | <51 | 47.9 | − 4.22 | 1.6(06) | <6.9(12) | <2.1(−11) |
| CH3OH 505–404 (A) | <51 | 34.8 | − 4.22 | 4.3(05) | <4.1(12) | <1.3(−11) | |
| CH3OH 110–101 (A) | <26 | 16.9 | − 3.49 | 4.3(07) | <7.0(11) | <2.2(−12) | |
| CH3OH 211–202 (A) | <26 | 21.6 | − 3.49 | 5.0(06) | <5.0(11) | <1.6(−12) | |
| TW Hya | CH3OH stackedb | 26.5 ± 2.7 | 28.6 | − 3.49 | 3.0(06) | 4.7(12) | 1.1(−12) |
Notes. The disk-averaged column density is calculated using Eq. (1) with Tex = 25 K. The format a(b) translates toa × 10b. Flux errors are dominated by systematic uncertainties, taken to be 10%. (a) Upper limits are derived at the 3σ level using the HD 163296 Keplerian mask (Sect. 3). (b) The stacked detection consists of three CH3OH transitions: CH3OH 211 –202 (A) at 304.208 GHz, CH3OH 312 –303 (A) at 305.472 GHz, and CH3OH 413 –404 (A) at 307.166 GHz. Excitation parameters for the CH3 OH 312 –303 (A) line are used to calculate column density. References.Rabli & Flower (2010); Walsh et al. (2016).
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