Lightcurve results for 22489 Yanaka.
No reliable period could be determined.
Asteroid 22489 Yanaka is a main belt asteroid with an estimated diameter of 10 km. It was discovered on April 7, 1997 by A. Nakamura at Kuma Kogen. The semi-major axis is 2.42 AU, the eccentricity is 0.192 and the inclination is 12.18 degrees.
This asteroid was observed on 2 nights during April 2010 when it was in the field of another asteroid I was observing. Analysis of the data was very frustrating as the asteroid was quite faint. This meant that the lightcurve was dominated by noise and no reliable period could be determined.