This licentiate thesis is based on two scientific articles on the subject of dark matter in the Milky Way. The first article is about dark matter capture by the Sun. If dark matter is constituted by Weakly Interacting Massive Particles (WIMPs), then such particles would be captured by the Sun and other massive bodies. A first scattering event would bind the WIMP in orbit. With further collisions, more kinetic energy would be lost, such that the WIMP would eventually sink to the bottom of the Sun’s gravitational well and thermalize to the Sun’s core temperature. In this first article, I explore this thermalization process and its time scale. I find that the common assumption of instantaneous thermalization is valid in most cases of interest. In the second article, written with Dr. Giacomo Monari, we make a dynamical mass measurement of the galactic disk in the solar neighbourhood, using astrometric data from the Tycho-Gaia Astrometric Solution (TGAS). We improve on previous studies especially in terms of statistical modelling and account for observational errors on all individual stars. We find a local dynamical matter density that is in accordance with most other studies.