A new mechanical stellar wind feedback model for the Rosette Nebula
  The famous Rosette Nebula has an evacuated central cavity formed from the
stellar winds ejected from the 2-6 million-year-old co-distant and co-moving
central star cluster NGC 2244. However, with upper age estimates of less than
110,000 years, the central cavity is too young compared to NGC 2244 and
existing models do not reproduce its properties. A new proper motion study
herein using Gaia data reveals the ejection of the most massive star in the
Rosette, HD46223, from NGC 2244 occurred 1.73 (+0.34,-0.25)Myr (1$\sigma$
uncertainty) in the past. Assuming this ejection was at the birth of the most
massive stars in NGC 2244, including the dominant centrally positioned HD46150,
the age is set for the famous ionised region at more than ten times that
derived for the cavity. Here, we are able to reproduce the structure of the
Rosette Nebula, through simulation of mechanical stellar feedback from a
40M$_{\odot}$ star in a thin sheet-like molecular cloud. We form the
135,000M$_{\odot}$ cloud from thermally-unstable diffuse interstellar medium
under the influence of a realistic background magnetic field with
thermal/magnetic pressure equilibrium. Properties derived from a snapshot of
the simulation at 1.5Myr, including cavity size, stellar age, magnetic field
and resulting inclination to the line of sight, match those derived from
observations. An elegant explanation is thus provided for the stark contrast in
age estimates based on realistic diffuse ISM properties, molecular cloud
formation and stellar wind feedback.
