Can the James Webb Space Telescope detect isolated population III stars?

TL;DR

This paper evaluates whether the James Webb Space Telescope can detect isolated population III stars at high redshifts, concluding that detection is unlikely due to low surface densities despite potential gravitational lensing benefits.

Contribution

It provides a detailed calculation of the detectability of isolated population III stars with JWST, incorporating realistic stellar atmospheres and gravitational lensing effects.

Findings

Detection of individual population III stars with JWST is unlikely at z=10-20.

Gravitational lensing can boost flux but does not significantly improve detection prospects.

Surface number densities of these stars are too low for reliable detection.

Abstract

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.