We find a new substellar companion to the Pleiades member star , Pleiades HII 3441 , using the Subaru telescope with adaptive optics .
The discovery is made as part of the high-contrast imaging survey to search for planetary-mass and substellar companions in the Pleiades and young moving groups .
The companion has a projected separation of 0 \farcs 49 \pm 0 \farcs 02 ( 66 \pm 2 AU ) and a mass of 68 \pm 5 M _ { J } based on three observations in the J - , H - , and K _ { S } -band .
The spectral type is estimated to be M7 ( \sim 2700 K ) , and thus no methane absorption is detected in the H band .
Our Pleiades observations result in the detection of two substellar companions including one previously reported among 20 observed Pleiades stars , and indicate that the fraction of substellar companions in the Pleiades is about 10.0 ^ { +26.1 } _ { -8.8 } % .
This is consistent with multiplicity studies of both the Pleiades stars and other open clusters .