Table 2
Top part: astrophysical parameters of the selected discs. Bottom part: summary of the observations.
| HD 100546 | HD 100453 | HD 169142 | HD 179218 | |
|---|---|---|---|---|
| Spec. type | B9Vne | A9Ve | B9V | A0Ve |
| Temp. (K) | 10 500 | 7600 | 8250 | 9640 |
| Lum. (L⊙) | 32 | 10 | 8.55 | 182 |
| M (M⊙) | 2.4 | 1.8 | 1.69 | 3.66 |
| Age (Myr) | >10 | 15 (10 ?) | 6 | 1.08 |
| d (pc) | 109 | 104 | 117 | 245 |
| G0 at 50 au | 4.2 × 106 | 2.4 × 105 | 3.4 × 105 | 1.6 × 107 |
| I3.3 (10−14 W/m2) | 2.5 ± 0.5 | 1.3 ± 0.2 | 1 ± 0.2 | 1.7 ± 0.2 |
| FWHM (au) | 12 (up to 50) | 20 | 4 3 | 35 |
| Date | 2005/03/26 | 2005/03/30 | 2005/05/05 | 2005/07/14 |
| Airmass | 1.56 | 1.17 | 1.01 | 1.32 |
| SR (%) | 46 | 38 | 37 | 53 |
| r0 (cm) | 16 | 8 | 11 | 14 |
| L0 (m) | 25 | 19 | 18 | 17 |
| Seeing (′′) | 0.66 | 1.17 | 0.93 | 0.69 |
Notes. Top part: The standard star used for data reduction is HR6572. We list spectral type, effective temperature, luminosity, mass, and age (Seok & Li 2017). The distance is taken from Gaia Collaboration (2018). G0 is the far-UV flux strength at 50 au from the star expressed in units of the average interstellar radiation field, i.e. 1.6 × 10−3 erg s−1 cm−2 (Habing 1968). The integrated strength of the aromatic 3.3 μm feature is taken from Habart et al. (2004). Estimates of the radial spatial extension of the 3.3 μm band (FWHM) for HD 100546, HD 100453 and HD 169142 are from Geers et al. (2007b); Habart et al. (2006). FWHM for HD 17918 is derived from this work. Bottom part: SR is the Strehl ratio or coherent energy. r0 is the Fried parameter. L0 is the outer scale.
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