Can the James Webb Space Telescope detect isolated population III stars?
  Isolated population III stars are postulated to exist at approximately
z=10-30 and may attain masses up to a few hundred solar masses. The James Webb
Space telescope (JWST) is the next large space based infrared telescope and is
scheduled for launch in 2014. Using a 6.5 meter primary mirror, it will
probably be able to detect some of the first galaxies forming in the early
Universe. A natural question is whether it will also be able to see any
isolated population III stars. Here, we calculate the apparent broadband
AB-magnitudes for 300 solar masses population III stars in JWST filters at
z=10-20. Our calculations are based on realistic stellar atmospheres and take
into account the potential flux contribution from the surrounding HII region.
The gravitational magnification boost achieved when pointing JWST through a
foreground galaxy cluster is also considered. Using this machinery, we derive
the conditions required for JWST to be able to detect population III stars in
isolation. We find that a detection of individual population III stars with
JWST is unlikely at these redshifts. However, the main problem is not
necessarily that these stars are too faint, once gravitational lensing is taken
into account, but that their surface number densities are too low.
