Observational constraints on supermassive dark stars

Some of the first stars could be cooler and more massive than standard stellar models would suggest, due to the effects of dark matter annihilation in their cores. It has recently been argued that such objects may attain masses in the 10(4)-10(7) M-circle dot range and that such supermassive dark stars should be within reach of the upcoming James Webb Space Telescope. Notwithstanding theoretical difficulties with this proposal, we argue here that some of these objects should also be readily detectable with both the Hubble Space Telescope and ground-based 8-10 m class telescopes. Existing survey data already place strong constraints on 10(7) M-circle dot dark stars at z approximate to 10. We show that such objects must be exceedingly rare or short lived to have avoided detection.