25/ago/17 – Detection of the Yarkovsky and YORP effect for young asteroid families (Valerio Carruba, UNESP)

Young families are families that formed in timescales of 20 Myr or less^2,4.   Because of their very young age, chaotic dynamics did not had enough time to erase traces of the event that formed the family.  The longitudes of node (and, in some cases, of pericenter)  of the family members converge to within a very limited range when integrated backward over the estimated age of the family. This allows to i) identify family members and ii) estimate the family age with a precision not available for other, older asteroid groups. While this behavior was studied and understood in previous works^3,4, discoveries of new asteroids over the last ten years dramatically improved the number of young asteroid families such as Karin, a subfamily of the Koronis asteroid family, Veritas, Iannini, and others.

Here we took advantage of this new larger sample to i) refine the age estimate of these families, and ii) detect and study the impact that the YORP effect has had on the group dynamical evolution¹.  The Karin family should be 5.764+/-0.011 Myr old, and the YORP effect was most likely responsible for affecting the spin obliquity distribution of the D < 2 km sized Karin population, producing a bimodal distribution.  Preliminary results for other young families may also briefly discussed in this work. [/av_textblock] [/av_four_fifth]