First Investigation of the Combined Impact of Ionizing Radiation and
  Momentum Winds from a Massive Star on a Self-Gravitating Core
  Massive stars shape the surrounding ISM by emitting ionizing photons and
ejecting material through stellar winds. To study the impact of the momentum
from the wind of a massive star on the surrounding neutral or ionized material,
we implemented a new HEALPix-based momentum conserving wind scheme in the
Smoothed Particle Hydrodynamics (SPH) code SEREN. A qualitative study of the
impact of the feedback from an O7.5-like star on a self gravitating sphere
shows that, on its own, the transfer of momentum from a wind onto cold
surrounding gas has both a compressing and dispersing effect. It mostly affects
gas at low and intermediate densities. When combined with a stellar source's
ionizing UV radiation, we find the momentum driven wind to have little direct
effect on the gas. We conclude that, during a massive star's main sequence, the
UV ionizing radiation is the main feedback mechanism shaping and compressing
the cold gas. Overall, the wind's effects on the dense gas dynamics and on the
triggering of star formation are very modest. The structures formed in the
ionization-only simulation and in the combined feedback simulation are
remarkably similar. However, in the combined feedback case, different SPH
particles end up being compressed. This indicates that the microphysics of gas
mixing differ between the two feedback simulations and that the winds can
contribute to the localized redistribution and reshuffling of gas.
