  Surface photometry detections of red and exceedingly faint halos around
galaxies have resurrected the old question of whether some non-negligible
fraction of the missing baryons of the Universe could be hiding in the form of
faint, hydrogen-burning stars. The optical/near-infrared colours of these red
halos have proved very difficult to reconcile with any normal type of stellar
population, but can in principle be explained by advocating a bottom-heavy
stellar initial mass function. This implies a high stellar mass-to-light ratio
and hence a substantial baryonic mass locked up in such halos. Here, we explore
the constraints imposed by current observations of ordinary stellar halo
subdwarfs on a putative red halo of low-mass stars around the Milky Way.
Assuming structural parameters similar to those of the red halo recently
detected in stacked images of external disk galaxies, we find that a smooth
halo component with a bottom-heavy initial mass function is completely ruled
out by current star count data for the Milky Way. All viable smooth red halo
models with a density slope even remotely similar to that of the stacked halo
moreover contain far too little mass to have any bearing on the missing-baryon
problem. However, we note that these constraints can be sidestepped if the red
halo stars are locked up in star clusters, and discuss potential observations
of other nearby galaxies that may be able to put such scenarios to the test.
