  Rotation period clustering in prograde/retrograde rotators might indicate the
preliminary indication of the Slivan state in the Koronis family as a result of
the YORP effect. We follow the general scenario of dispersion in semimajor axis
of the asteroid family members to separate prograde and retrograde rotators in
the Koronis family. From the available rotation periods obtained from PTF/iPTF,
we can not found the rotation period clustering of objects with H grater than
12 mag in the Koronis family. This could be the result of the intermittent
collisional process of small asteroids (D less than ~20 km) which leads to
astray Yarkovsky drifting. Measurement of the pole orientations of our sample
will verify our preliminary result and validate our method.
