Asteroids of size larger than 0.15 km generally do not have periods smaller than 2.2 hours , a limit known as cohesionless spin-barrier .
This barrier can be explained by the cohesionless rubble-pile structure model .
There are few exceptions to this “ rule ” , called LSFRs ( Large Super-Fast Rotators ) , as ( 455213 ) 2001 OE84 , ( 335433 ) 2005 UW163 and 2011 XA3 .
The near-Earth asteroid ( 436724 ) 2011 UW158 was followed by an international team of optical and radar observers in 2015 during the flyby with Earth .
It was discovered that this NEA is a new candidate LSFR .
With the collected lightcurves from optical observations we are able to obtain the amplitude-phase relationship , sideral rotation period ( PS = 0.610752 \pm 0.000001 h ) , a unique spin axis solution with ecliptic coordinates \lambda = 290 ^ { \circ } \pm 3 ^ { \circ } , \beta = – 39 ^ { \circ } \pm 2 ^ { \circ } and the asteroid 3D model .
This model is in qualitative agreement with the results from radar observations .