Binaries Among Debris Disk Stars

We have gathered a sample of 112 main-sequence stars with known debris disks. We collected published information and performed adaptive optics obser-vations at Lick Observatory to determine if these debris disks are associated with binary or multiple stars. We discovered a previously unknown M-star companion to HD 1051 at a projected separation of 628 AU. We found that 25 ± 4 % of our debris disk systems are binary or triple star systems, substantially less than the expected ∼ 50%. The period distribution for these suggests a relative lack of sys-tems with 1–100 AU separations. Only a few systems have blackbody disk radii comparable to the binary/triple separation. Together, these two characteristics suggest that binaries with intermediate separations of 1–100 AU readily clear out their disks. We find that the fractional disk luminosity, as a proxy for disk mass, is generally lower for multiple systems than for single stars at any given age. Hence, for a binary to possess a disk (or form planets) it must either be a very widely separated binary with disk particles orbiting a single star or it must be a small separation binary with a circumbinary disk