the range of 0.24–0.34. It has an extremely well-measured rotation period of 10.2 hours. Its rotation period is slowly increasing due to the YORP effect. References External links Lightcurve plot of 1685 Toro, Palmer Divide Observatory, B. D. Warner (2012) Lightcurve Database Query (LCDB), at www.minorplanet.info Dictionary of Minor Planet Names, Google books 001685 Discoveries by Carl A. Wirtanen Named minor planets 001685 001685 19480717