A New Galactic Wolf-Rayet Star in Centaurus

摘要

I communicate the detection of a new Galactic Wolf-Rayet star (WR60a) in Centaurus. The H- andK-band spectra of WR60a show strong carbon near-infrared emission lines, characteristic of Wolf-Rayet stars of theWC5-7 subtype. Adopting mean absolute magnitudeMKand mean intrinsic (J-KS) and (H-KS) colours, it was found that WR60a suffers a mean visual extinction of3.8±1.3magnitudes, being located at a probable heliocentricdistance of5.2±0.8 Kpc, which for the related Galactic longitude (l=312) puts this star probably in the Carina-Sagittarius arm at about 5.9 kpc from the Galactic center. I searched for clusters in the vicinity of WR60a and in principle found no previously known clusters in a search radius region of several tens arcminutes. The detection of awell-isolated WR star induced us to seek for some still unknown cluster, somewhere in the vicinity of WR60a. Frominspection of 5.8 μm and 8.0 μm Spitzer/IRAC GLIMPSE images of the region around the new WR star, strong mid-infrared extended emission at about 13.5 arcmin south-west of WR60a was found. The study of the H-KScolourdistribution of point sources associated with the extended emission reveals the presence of a new Galactic clustercandidate probably formed by at least 85 stars.