  We studied the rate at which stars capture dark matter (DM) particles,
considering different assumptions regarding the DM characteristics and in
particular investigating how the stellar physics influences the capture rate.
Two scenarios were considered: first, we assumed the maximal values for the
spin-dependent and spin-independent DM particle-nucleon scattering cross
sections allowed by the limits from direct detection experiments. Second, we
considered that both scattering cross sections are of the same order, with the
aim of studying the dependencies of the capture rate on stellar elements other
than hydrogen. We found that the characteristics of the capture rate are very
different in the two scenarios. Furthermore, we quantified the uncertainties on
the computed capture rate (C_x) and on the ratio between the luminosities from
DM annihilations and thermonuclear reactions (L_x/L_nuc) derived from an
imprecise knowledge of the stellar structure and DM parameters. For instance,
while an uncertainty of 10% on the typical DM velocity leads to similar errors
on the computed C_x and L_x/L_nuc, the same uncertainty on the stellar mass
becomes more relevant and duplicates the errors. Our results may be used to
evaluate the reliability of the computed capture rate for the hypothetical use
of stars other than the Sun as DM probes.
