  In this work I report the discovery of a new Galactic O2 If*/WN6 star, a rare
member of the extremely massive hydrogen core-burning group of stars that due
its high intrinsic luminosity (close to the Eddington limit), possess an
emission-line spectrum at the beginning of their main-sequence evolution,
mimicking the spectral appearance of classical WR stars. The new star is named
WR42e and is found in isolation at 2.7 arcmin (about 6 pc) from the core of the
star-burst cluster NGC3603. From the computed E(B-V) color excess and observed
visual magnitude it was possible to estimate its absolute visual magnitude as
MV =-6.3 mag, which is a value similar to those obtained by other researchers
for stars of similar spectral type both, in the Galaxy and in the Large
Magellanic Cloud. Considering the derived absolute visual magnitude, we
computed a bolometric stellar luminosity of about 3.2x106 Lsun. Finally, the
mass of the new O2If*/WN6 star was estimated by comparing its observed
magnitudes and colors with those of other probable NGC3603 cluster members,
founding that the WR42e initial mass possibly exceeds 100 Msun.
