YORP effect

Not to be confused with Yarkovsky effect.
A spherical asteroid with two wedge-shaped projections. Re-radiated light from the "B" fin has the same magnitude as the "A" fin, but is not parallel to the incoming light. This produces a torque on the object.

The Yarkovsky–O'Keefe–Radzievskii–Paddack effect, or YORP effect for short, changes the rotation state of a small astronomical body – that is, the body's spin rate and the obliquity of its pole(s) – due to the scattering of solar radiation off its surface and the emission of its own thermal radiation.

The YORP effect is typically considered for asteroids with their heliocentric orbit in the Solar System. The effect is responsible for the creation of binary and tumbling asteroids as well as for changing an asteroid's pole towards 0°, 90°, or 180° relative to the ecliptic plane and so modifying its heliocentric radial drift rate due to the Yarkovsky effect.