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L. J. Hadfield (SSC/Caltech/U. Sheffield), S. D. Van Dyk (SSC/Caltech), A. P. Marston (Herschel Science Centre/ESA), P. W. Morris (NHSC/IPAC/Caltech), J. D. T. Smith (U. Arizona)
Massive stars have an unparalleled effect on galaxy evolution, since their strong stellar winds and the inevitable supernovae/hypernovae input energy and chemical elements into the interstellar medium. O-type stars are thought to evolve through, possibly, the red supergiant phase, and then the luminous blue variable phase to become H-poor Wolf-Rayet (WR) stars, before explosion. Due to their high luminosity, the presence of WR stars can be detected in the integrated spectra of galaxies, and the short duration of this phase of massive stellar evolution makes WR stars excellent probes of very recent star formation, metallicity, and the initial mass function in the nearby Universe. Unfortunately, the number of known WR stars in the Milky Way is deficient by factors of 4 to 10, depending on the models, and as a result we know relatively little about the total massive star formation and the fate of massive stellar evolution in our own Galaxy. The reason is most likely the rapid increase with distance of the line-of-sight extinction, due to dust in the Galactic Plane, where most WR stars are located. Detecting new WR stars is greatly enhanced in the infrared, where extinction is substantially lower. Since merging the mid- and near-infrared continuum should provide a powerful means of identifying a significant number of hidden WR stars in the Plane, we are analyzing the combination of the Spitzer GLIMPSE Legacy and 2MASS surveys. Here we present early results from our work, including confirmation of new WR stars we have detected in the GLIMPSE fields.
The author(s) of this abstract have provided an email address for comments about the abstract: lucy@ipac.caltech.edu
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.