Observed separation between GQ Lupi and its companion

Observed separations between the primary star GQ Lupi and its companion, as deduced from the images taken with HST in 1999 (left), Subaru in 2002 (middle) and NACO on the VLT in 2004 (right). All the observed separations are consistent with no changes in separation, implying the two objects move in the same direction (red line). The curved line shows the change in separation expected if the faint object was a background star, due to the proper motion of GQ Lup.