While collisional families are common in the asteroid belt , only one is known in the Kuiper belt , linked to the dwarf planet Haumea .
The characterization of Haumea ’ s family helps to constrain its origin and , more generally , the collisional history of the Kuiper belt .
However , the size distribution of the Haumea family is difficult to constrain from the known sample , which is affected by discovery biases .
Here , we use the Outer Solar System Origins Survey ( OSSOS ) Ensemble to look for Haumea family members .
In this OSSOS XVI study we report the detection of three candidates with small ejection velocities relative to the family formation centre .
The largest discovery , 2013 UQ _ { 15 } , is conclusively a Haumea family member , with a low ejection velocity and neutral surface colours .
Although the OSSOS Ensemble is sensitive to Haumea family members to a limiting absolute magnitude ( H _ { r } ) of 9.5 ( inferred diameter of \sim 90 km ) , the smallest candidate is significantly larger , H _ { r } = 7.9 .
The Haumea family members larger than \simeq 20 km in diameter must be characterized by a shallow H -distribution slope in order to produce only these three large detections .
This shallow size distribution suggests that the family formed in a graze-and-merge scenario , not a catastrophic collision .