Asteroid 9090 Chirotenmondai

Asteroid 9090 Chirotenmondai is a main belt asteroid with an estimated diameter of 10 km. It was discovered on October 28, 1995 by K. Endate and K. Watanabe at Kitami. The semi-major axis is 2.53 AU, the eccentricity is 0.097 and the inclination is 13.75 degrees.

This asteroid was observed on 5 nights during March and April 2006. The resulting lightcurve was noisy, but indicated a period of 5.695 hours.

Lightcurve results for 9090 Chirotenmondai.
Derived period 5.695 +/- 0.002 hours. Amplitude 0.35 +/- 0.05 magnitude.

I was able to observe Chirotenmondai on 5 nights during December/January 2014/15. Although the resulting lightcurve was still somewhat noisy, a good lightcurve was obtained which showed a period of 5.6475 hours, in broard agreement with the earlier result.

Lightcurve results for 9090 Chirotenmondai in 2014/15.
Derived period 5.6475 +/- 0.0002 hours. Amplitude 0.17 +/- 0.05 magnitude.