Table 6
Model parameters for four well-fitting disc models.
| (1) | (2) | (3)∗ | (4) | ||
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| Quantity | Symbol | “low UV” | “high UV” | Fully mixed | Power-law density profile |
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| disc mass | Mdisc | 2.2 × 10-2 M⊙ | 2.0 × 10-2 M⊙ | 7.1 × 10-2 M⊙ | 1.1 × 10-2 M⊙ |
| column density power index | ϵ | n/a | n/a | n/a | 0.085 |
| reference scale height | H0 | 0.019 AU | 0.019 AU | 0.019 AU | 0.027 AU |
| flaring power | β | 1.068 | 1.066 | 1.066 | 1.019 |
| gas-to-dust mass ratio | ρ/ρd | 21.8 | 20.5 | 101.1 | 9.1 |
| minimum dust particle radius | amin | 5.95 × 10-3 μm | 1.25 × 10-3 μm | 9.63 × 10-3 μm | 1.24 × 10-2 μm |
| maximum dust particle radius | amax | 1134 μm | 1405 μm | 2041 μm | 1015 μm |
| dust size dist. power index | p | 3.61 | 3.57 | 3.68 | 3.75 |
| dust settling parameter | s | 0.57 | 0.39 | 0 (fixed) | 0.56 |
| minimum dust settling radius | aset | 1.09 μm | 0.44 μm | n/a | 0.81 |
| PAH abundance relative to ISM | fPAH | 4.3 × 10-2 | 3.5 × 10-2 | 6.8 × 10-3 | 2.2 × 10-2 |
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| fit to observed photometry | χPHOT | 1.723 | 2.061 | 1.323 | 1.279 |
| fit to ISO-SWS spectrum | χISO | 1.326 | 1.378 | 1.780 | 0.827 |
| fit to observed line data | χLINE | 0.661 | 0.741 | 0.742 | 0.607 |
Notes. The first three columns refer to models with exponentially-tapered density profiles, while model 4 is a simple power law. Models 1, 3 and 4 are for a “low UV” input spectrum while model 2 is for a “high UV” flux. Finally, models 1, 2, and 4 allow dust grains to settle towards the midplane while model 3 is fully mixed. Model 3 represents our overall “preferred” model, which is later discussed in detail, and is marked by an asterisk.
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