Planet formation is unlikely in equal mass binary systems with a ∼ 50 AU

We show that planet formation via both gravitational collapse and core accretion is unlikely to occur in equal mass binary systems with moderate (∼ 50 AU) semimajor axes. Internal thermal energy generation in the disks is sufficient to heat the gas everywhere so that spiral structures quickly decay rather than grow or fragment. This same heating will inhibit dust coagulation because the temperatures rise above the vaporization temperatures of many volatile materials. We consider other processes not included in the model and conclude that our temperatures are conservatively estimated (low), i.e. planet formation is less likely in real systems than in the model. Subject headings: stars:formation, stars:planetary systems