The ideal place to study massive star formation and evolution is our own Galaxy, where we can resolve objects on small linear scales and have some hope of complete samples. It would be of great interest to find all the WR stars in our galaxy to test stellar evolution theories at high metallicity, and to learn about environments of massive star formation. Another important benefit is the study of Galactic structure as traced by young star-forming regions.
Surveys for emission line stars in the Milky Way using the narrow band technique have been done before, but in the optical, where extinction by intervening dust is highly problematic (Shara et al. 1999). However, these surveys firmly establish WR stars as key tracers of star formation, both in the Milky Way and other galaxies (Conti 1991). By moving to the NIR, we can identify these objects in regions where heavy reddening renders them undetectable in the optical.
With a simple model for the distribution of Galactic WR stars,
Shara et al. (1999)
demonstrate the difficulty in conducting WR searches in the
optical. Because of high extinction in the plane,
the vast majority (
90%) of the Milky Way's
massive stellar population is hidden from view by obscuring dust.
They also showed how this could be overcome by moving to the
infrared, indicating that the number of WR stars as a
function of magnitude peaks at K=13-14. It is clear that
NIR surveys within the plane
of our Galaxy are essential to significantly enlarge the known population
of WR stars.
Copyright ESO 2003