V4046 Sgr is a young 20 Myr old binary star. It also hosts a protoplanetary disk. Using the instrument SPHERE, a planet finder mounted at the Very Large Telescope (Chile), a team leaded by Valentina D’Orazi (OAPD/INAF), which includes Alice Zurlo (UDP), discovered that the secondary star is casting a shadow on the protoplanetary disk.
Using the phase difference due to light travel time they managed to measure the flaring of the disk and the geometrical distance of the system. The distance is in very good agreement with the value obtained from the Gaia mission’s Data Release 2 (DR2), and flaring angles of α = (6.2 ± 0.6)° and α = (8.5 ± 1.0)° for the inner and outer disk rings, respectively. This technique opens up a path to explore other binary systems, providing an independent estimate of distance and the flaring angle, a crucial parameter for disk modelling.