A New Galactic Wolf-Rayet Star in Centaurus

Abstract

In this work I communicate the detection of a new Galactic Wolf-Rayet star (WR60a) in Centaurus. The H- and K-band spectra of WR60a, show strong carbon near-infrared emission lines, characteristic of Wolf-Rayet stars of the WC5-7 sub-type. Adopting mean absolute magnitude M${}_K$ and mean intrinsic ($J-K_S$) and ($H-K_S$) colours, it was found that WR60a suffer a mean visual extinction of 3.8$\pm$1.3 magnitudes, being located at a probable heliocentric distance of 5.2$\pm$0.8 Kpc, which for the related Galactic longitude (l=312) puts this star probably in the Carina-Sagittarius arm at about 5.9 kpc from the Galactic center. I searched for clusters in the vicinity of WR60a, and in principle found no previously known clusters in a search radius region of several tens arc-minutes. The detection of a well isolated WR star induced us to seek for some still unknown cluster, somewhere in the vicinity of WR60a. From inspection of 5.8$\mu$m and 8.0$\mu$m Spitzer/IRAC GLIMPSE images of the region around the new WR star, it was found strong mid-infrared extended emission at about 13.5 arcmin south-west of WR60a. The study of the the H-K${}_S$ colour distribution of point sources associated with the extended emission, reveals the presence of a new Galactic cluster candidate probably formed by at least 85 stars.

5 pages, 2 tables and 4 figures. Figure 4 is in low-resolution mode. The published on-line version of the paper can be obtained at http://www.isrn.com/journals/astro/2011/632850/

References in corpus (5)

• The initial conditions of stellar protocluster formation. I. A catalogue of Spitzer dark clouds
• A census of the Wolf-Rayet content in Westerlund 1 from near-infrared imaging and spectroscopy
• Searching for hidden Wolf-Rayet stars in the Galactic Plane - 15 new Wolf-Rayet stars
• 12 New Galactic Wolf-Rayet Stars Identified via 2MASS+Spitzer/GLIMPSE
• SOAR-OSIRIS observations of the Sh 2-307 HII region: Triggered star formation beyond the solar circle