We present the results of a high-resolution imaging survey for brown dwarf binaries in the Pleiades open cluster .
The observations were carried out with the Advance Camera for Surveys ( 42 ) onboard the Hubble Space Telescope .
Our sample consists of 15 bona-fide brown dwarfs .
We confirm 2 binaries and detect their orbital motion , but we did not resolve any new binary candidates in the separation range between 5.4 AU and 1700 AU and masses in the range 0.035–0.065 M _ { \sun } .
Together with the results of our previous study ( 29 ) , we can derive a visual binary frequency of 13.3 ^ { +13.7 } _ { -4.3 } % for separations greater than 7 AU masses between 0.055–0.065 M _ { \sun } and mass ratios between 0.45–0.9 < q < 1.0 .
The other observed properties of Pleiades brown dwarf binaries ( distributions of separation and mass ratio ) appear to be similar to their older counterparts in the field .