An O2If*/WN6 Star Catch in the Act in a Compact Hii region in the
  Starburst Cluster NGC 3603
  In this paper I report the discovery of an O2If*/WN6 star probably still
partially embedded in its parental cocoon in the star-burst cluster NGC 3603.
From the observed size of the associated compact Hii region, it was possible to
derive a probable dynamic age of no more than 600,000 years. Using the computed
visual extinction value Av ~ 6 magnitudes, an absolute visual magnitude Mv
=-5.7 mag is obtained, which for the assumed heliocentric distance of 7.6 kpc
results in a bolometric luminosity of ~ 8x10^5 Lsun. Also from the V magnitude
and the V-I color of the new star, and previous models for NGC3603's massive
star population, we estimate its mass for the binary (O2If*/WN6 + O3If) and the
single-star case (O2If*/WN6). In the former, it was found that the initial mass
of each component possibly exceeded 80 Msun and 40 Msun, while in the latter
MTT 58's initial mass possibly was in excess of 100 Msun.
