  To characterize the meteoroid environment around Mercury and its contribution
to the planet's exosphere, we combined four distinctive sources of meteoroids
in the solar system: main-belt asteroids, Jupiter family comets, Halley-type
comets, and Oort Cloud comets. All meteoroid populations are described by
currently available dynamical models. We used a recent calibration of the
meteoroid influx onto Earth as a constraint for the combined population model
on Mercury. We predict vastly different distributions of orbital elements,
impact velocities and directions of arrival for all four meteoroid populations
at Mercury. We demonstrate that the most likely model of Mercury's meteoroid
environment- in the sense of agreement with Earth -provides good agreement with
previously reported observations of Mercury's exosphere by the MESSENGER
spacecraft and is not highly sensitive to variations of uncertain parameters
such as the ratio of these populations at Earth, the size frequency
distribution, and the collisional lifetime of meteoroids. Finally, we provide a
fully calibrated model consisting of high-resolution maps of mass influx and
surface vaporization rates for different values of Mercury's true anomaly
angle.
