  We study K-type asteroids in the broad surroundings of the Eos family because
they seem to be intimately related, according to their colours measured by the
Sloan Digital Sky Survey. Such `halos' of asteroid families have been rarely
used as constraints for dynamical studies to date. We explain its origin as
bodies escaping from the family `core' due to the Yarkovsky semimajor-axis
drift and interactions with gravitational resonances, mostly with the 9/4
mean-motion resonance with Jupiter at 3.03 AU. Our N-body dynamical model
allows us to independently estimate the age of the family 1.5 to 1.9 Gyr. This
is approximately in agreement with the previous age estimate by Vokrouhlick\'y
et al. (2006) based on a simplified model (which accounts only for changes of
semimajor axis). We can also constrain the geometry of the disruption event
which had to occur at the true anomaly f =~ 120 to 180 deg.
