Best fit of the data from ROASTERR-1 Obs.(2) to the convolved square-well model. The flux from the occulted star plus 2003 VS₂ is plotted with black dots, normalized to the flux of the star while unocculted. Time is in seconds after 2019 October 22–20:40:00 UT. The gray-dashed line represents the initial square-well model; the solid blue line represents the final fit, after convolving the square-well model by Fresnel diffraction, the exposure time, and the stellar diameter, see Sect. 3.2 for details. The open blue circles show the expected flux from this model. The stellar occultation starting and ending times derived are plotted in red, with their uncertainties. For all the positive chords, the star disappearance and reappearance times and chord lengths derived are listed in Table 5.