The results of a search for sub-km Kuiper Belt Objects ( KBOs ) with the method of serendipitous stellar occultations are reported .
Photometric time series were obtained on the 1.8m telescope at the Dominion Astrophysical Observatory ( DAO ) in Victoria , British Columbia , and were analyzed for the presence of occultation events .
Observations were performed at 40 Hz and included a total of 5.0 star-hours for target stars in the ecliptic open cluster M35 ( \beta = 0.9 \arcdeg ) , and 2.1 star-hours for control stars in the off-ecliptic open cluster M34 ( \beta = 25.7 \arcdeg ) .
To evaluate the recovery fraction of the analysis method , and thereby determine the limiting detectable size , artificial occultation events were added to simulated time series ( 1/f scintillation-like power-spectra ) , and to the real data .
No viable candidate occultation events were detected .
This limits the cumulative surface density of KBOs to 3.5 \times 10 ^ { 10 } deg ^ { -2 } ( 95 % confidence ) for KBOs brighter than m _ { R } =35.3 ( larger than \sim 860m in diameter , assuming a geometric albedo of 0.04 and a distance of 40 AU ) .
An evaluation of TNO occultations reported in the literature suggests that they are unlikely to be genuine , and an overall 95 % -confidence upper limit on the surface density of 2.8 \times 10 ^ { 9 } deg ^ { -2 } is obtained for KBOs brighter than m _ { R } =35 ( larger than \sim 1 km in diameter , assuming a geometric albedo of 0.04 and a distance of 40 AU ) when all existing surveys are combined .