  Combining dynamical models of dust from Jupiter Family Comets and Halley-type
Comets, we demonstrate that the seasonal variation of the dust/meteoroid
environment at Mercury is responsible for producing the dawn-dusk asymmetry in
Mercury's exosphere observed by the MESSENGER spacecraft. Our latest models,
calibrated recently from ground-based and space-borne measurements, provide
unprecedented statistics that enable us to study the longitudinal and
latitudinal distribution of meteoroids impacting Mercury's surface. We predict
that the micrometeoroid impact vaporization source is expected to undergo
significant motion on Mercury's surface towards the nightside during Mercury's
approach to aphelion and towards the dayside when the planet is approaching the
Sun.
