Dark matter in the solar system III: The distribution function of WIMPs at the Earth from gravitational capture

Abstract

In this last paper in a series of three on weakly interacting massive particle (WIMP) dark matter in the solar system, we focus on WIMPs bound to the system by gravitationally scattering off of planets. We present simulations of WIMP orbits in a toy solar system consisting of only the Sun and Jupiter. As previous work suggested, we find that the density of gravitationally captured WIMPs at the Earth is small and largely insensitive to the details of elastic scattering in the Sun. However, we find that the density of gravitationally captured WIMPs may be affected by external Galactic gravitational fields. If such fields are unimportant, the density of gravitationally captured WIMPs at the Earth should be similar to the maximum density of WIMPs captured in the solar system by elastic scattering in the Sun. Using standard assumptions about the halo WIMP distribution function, we find that the gravitationally captured WIMPs contribute negligibly to direct detection event rates. While these WIMPs do dominate the annihilation rate of WIMPs in the Earth, the resulting event rate in neutrino telescopes is too low to be observed in next-generation neutrino telescopes.

24 pages, 11 figures, to be submitted

References in corpus (6)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Thin, thick and dark discs in LCDM
• Phase-space structure in the local dark matter distribution and its signature in direct detection experiments
• Dark matter in the solar system I: The distribution function of WIMPs at the Earth from solar capture
• Dark matter in the solar system II: WIMP annihilation rates in the Sun
• Velocity distributions in clusters of galaxies

Cited by in corpus (11)

• The Dark Matter at the End of the Galaxy
• Interpreting Dark Matter Direct Detection Independently of the Local Velocity and Density Distribution
• Dark matter in the solar system I: The distribution function of WIMPs at the Earth from solar capture
• Hydrogen Axion Star: Metallic Hydrogen Bound to a QCD Axion BEC
• A halo of trapped interstellar matter surrounding the solar system
• Dark Exoplanets
• Capture of primordial black holes in extrasolar systems
• Dark Kinetic Heating of Exoplanets and Brown Dwarfs
• Orbital Dynamics of the Solar Basin
• Direct detection signatures of a primordial Solar dark matter halo
• Gravitational Focusing of Low-Velocity Dark Matter on the Earth's Surface