YORP-Yarkowski evolution of asteroid families

According to [2], the coupling between obliquity and spin rate evolution drives the rotation state of small bodies into complex paths that may end up into equilibria. This behaviour not only significantly influences the spin dynamics of asteroids but it also affects their orbital evolution via the Yarkovsky effect which strongly depends on the obliquity of the body. To havea full picture of this dynamics it is essential to consider, in addition to the 'normal' Yorp (NYORP), also the so-called Tangential YORP (TYORP), caused by asymmetric light emission by boulders or other structures on the surface of an asteroid, and mutual collisions which cause step changes in the spin of asteroids. Introducing these effects in a model which tracks the coupled orbital and rotational evolution of asteroid families, under the action of the Yarkowsky (diurnal and seasonal), YORP and collision effects, we are able to recover the characteristic V-shape configuration in the semimajor axis vs absolute magnitude (H) space. The time evolution of a number of synthetic families is explored with this model looking in detail at different size regimes. Looking at time snapshots of the V-shape evolution the YORP-eye hypothesis of is probed too.