Other resonant near-Earth objects in addition to 2009 BD include 3753 Cruithne (the first to be discovered), (85770) 1998 UP1, 54509 YORP, 2001 GO2, 2002 AA29, 2003 YN107, (164207) 2004 GU9, and 2010 TK7 (an Earth trojan).
JPL includes non-gravitational acceleration parameters in the orbital solution.
Because 2009 BD is a very small multi-opposition near-Earth object, the effect of radiation pressure on the orbit caused by light from the Sun was able to be detected.
[4] The radiation-related acceleration allowed the Area to Mass Ratio (AMR) to be estimated at (2.97 ± 0.33) × 10−4 m2/kg.
Assuming an albedo of 0.12, a typical average for asteroids in the inner solar system, this AMR corresponds to a density of about 640 kg/m3.