The Effects of Asymmetric Dark Matter on Stellar Evolution I:
  Spin-Dependent Scattering
  Most of the dark matter (DM) search over the last few decades has focused on
WIMPs, but the viable parameter space is quickly shrinking. Asymmetric Dark
Matter (ADM) is a WIMP-like DM candidate with slightly smaller masses and no
present day annihilation, meaning that stars can capture and build up large
quantities. The captured ADM can transport energy through a significant volume
of the star. We investigate the effects of spin-dependent ADM energy transport
on stellar structure and evolution in stars with $0.9 \leq
M_{\star}/\mathrm{M}_{\odot} \leq 5.0$ in varying DM environments. We wrote a
MESA module that calculates the capture of DM and the subsequent energy
transport within the star. We fix the DM mass to 5 GeV and the cross section to
$10^{-37} \mathrm{cm{^2}}$, and study varying environments by scaling the DM
capture rate. For stars with radiative cores ($M_{\star} \lesssim 1.3\
\mathrm{M}_{\odot}$), the presence of ADM flattens the temperature and burning
profiles in the core and increases MS ($X_c > 10^{-3}$) lifetimes by up to
$\sim 20\%$. We find that strict requirements on energy conservation are
crucial to the simulation of ADM's effects on these stars. In higher-mass
stars, ADM energy transport shuts off core convection, limiting available fuel
and shortening MS lifetimes by up to $\sim 40\%$. This may translate to changes
in the luminosity and effective temperature of the MS turnoff in population
isochrones. The tip of the red giant branch may occur at lower luminosities.
The effects are largest in DM environments with high densities and/or low
velocity dispersions, making dwarf and early forming galaxies most likely to
display the effects.
