Searching for hidden Wolf–Rayet stars in the Galactic plane – 15 new Wolf–Rayet stars |
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| Authors: | L J Hadfield S D Van Dyk P W Morris J D Smith A P Marston D E Peterson |
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| Institution: | Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH;Spitzer Science Centre, IPAC, California Institute of Technology, M/C 220-6, Pasadena, CA 91125, USA;NASA Herschel Science Centre, IPAC, California Institute of Technology, M/C 100-22, Pasadena, CA 91125, USA;Steward Observatory, University of Arizona, Tucson, AZ 87512, USA;ESA/ESAC, Villafranca del Castillo, PO Box Apdo. 50727, 28080 Madrid, Spain;Department of Astronomy, University of Virginia, PO Box 400325, Charlottesville, VA 22904-4325, USA |
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| Abstract: | We report the discovery of 15 previously unknown Wolf–Rayet (WR) stars found as part of an infrared (IR) broad-band study of candidate WR stars in the Galaxy. We have derived an empirically based selection algorithm which has selected ～5000 WR candidate stars located within the Galactic plane drawn from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (mid-IR) and Two-Micron All-Sky Survey (near-IR) catalogues. Spectroscopic follow-up of 184 of these reveals 11 nitrogen-rich (WN) and four carbon-rich (WC) WR stars. Early WC subtypes are absent from our sample and none shows evidence for circumstellar dust emission. Of the candidates which are not WR stars, ～120 displayed hydrogen emission-line features in their spectra. Spectral features suggest that the majority of these are in fact B supergiants/hypergiants, ～40 of these are identified Be/Be] candidates.
Here, we present the optical spectra for six of the newly detected WR stars, and the near-IR spectra for the remaining nine of our sample. With a WR yield rate of ～7 per cent and a massive star detection rate of ～65 per cent, initial results suggest that this method is one of the most successful means for locating evolved, massive stars in the Galaxy. |
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| Keywords: | stars: Wolf–Rayet Galaxy: stellar content |
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