– 19 – H α line measured at 10% of its peak intensity, adopting the relation given by Natta et al. (2004): This relation is valid for 600 km/s > Δ V > 200 km/s (corresponding to 10 − 7 M$_{⊙}$/yr > M$_{acc}$ 10 − 11 M$_{⊙}$/yr) and can be applied to objects with a range of stellar (and sub-stellar) masses. The broadening of the the H α line is 1 to 2 orders of magnitude more sensitive to the presence of low accretion rates than other accretion indicators such as U-band excess and continuum veiling measurements (Muzerolle et al. 2003, Sicilia-Aguilar et al. (2006b), and is thus particularly useful to distinguish weakly accreting from non-accreting objects. However, as discussed by Nguyen et al. (2009), the 10% width measurements are also dependent on the line profile, rendering the 10% H α velocity width a relatively poor quantitive accretion indicator, specially at high accretion rates (Muzerolle et al. 1998). For the 9 objects we consider to be non-accreting, we adopt a mass accretion upper limit of 10 − $^{11}$M$_{⊙}$ /yr, corresponding to Δ V = 200 km/s. The so derived accretion rates (and upper limits) for our sample of transition disks are listed in Table 3. Given the large uncertainties associated with Equation 2 and the intrinsic variability of accretion in PMS stars, these accretion rates should be considered order-of-magnitude estimates. Seven binary systems were identified in our sample by visual inspection of the VLT-AO images: targets #5, 9, 15, 18, 23, 24, and 27 (Figure 4). The separation and flux ratios of these systems range from 0.19 ′′ to 1.68 ′′ and 1.0 to 12, respectively. All these systems were well resolved in both our J- and K$_{S}$-band images, which have typical FWHM values 4.4. Stellar companions Log ( M$_{acc}$ ( M$_{⊙}$/yr )) = − 12 . 89( ± 0 . 3) + 9 . 7( ± 0 . 7) × 10 − $^{3}$Δ V ( km/s ) (2)