Lightcurve analysis of NEA (190166) 2005 UP156: A new fully-synchronous binary

CCD photometric observations of the near-Earth
asteroid (190166) 2005 UP156 in 2017 May show it to
be a fully-synchronous binary with rotation and orbital
period P = 40.542 ± 0.008 h. The estimated effective
diameter ratio of the two bodies is 0.8 ± 0.1. However,
the 0.5 mag out-of-eclipse lightcurve indicates quite
elongated shapes and so the size ratio should be viewed
with caution.