The dispersal of protoplanetary disks around binary stars

Abstract

I present models of disk evolution around young binary stars. I show that the primary factor in determining circumbinary disk lifetimes is the rate of disk photoevaporation. I also find that photoevaporative clearing leaves a signature on the distribution of circumbinary disk lifetimes, with a sharp increase in disk lifetimes for binary separations a<~0.3-1AU. Observations of young binary stars can therefore be used to test models of disk evolution, and I show that current data set a strong upper limit to the rate of on-going photoevaporation (<1e-9 M_sun/yr). Finally I discuss the implications of these results for planet formation, and suggest that circumbinary planets around close (a<~1AU) binaries should be relatively common.