Title: Ejection of rocky and icy material from binary star systems: Implications for the origin and composition of 1I/`Oumuamua,
Abstract: In single star systems like our own Solar system, comets dominate the mass
budget of bodies that are ejected into interstellar space, since they form
further away and are less tightly bound. However 1I/`Oumuamua, the first
interstellar object detected, appears asteroidal in its spectra and in its lack
of detectable activity. We argue that the galactic budget of interstellar
objects like 1I/`Oumuamua should be dominated by planetesimal material ejected
during planet formation in circumbinary systems, rather than in single star
systems or widely separated binaries. We further show that in circumbinary
systems, rocky bodies should be ejected in comparable numbers to icy ones. This
suggests that a substantial fraction of additional interstellar objects
discovered in the future should display an active coma. We find that the rocky
population, of which 1I/`Oumuamua seems to be a member, should be predominantly
sourced from A-type and late B-star binaries.