Discovery of two Galactic Wolf-Rayet stars in Circinus

TL;DR

This paper reports the discovery of two new Wolf-Rayet stars in the Circinus region using near-infrared spectral data, identifying their sub-types and estimating their distances within our galaxy.

Contribution

The study introduces the first identification of two Galactic Wolf-Rayet stars in Circinus through archival near-infrared data, detailing their spectral types and potential locations.

Findings

WR67a is a WN6h type star with a spectrum similar to young, hydrogen-rich massive stars.

WR67b is a probable WC8 type star located approximately 2.7 kpc away.

Both stars are likely situated within the Scutum-Centaurus arm of the Milky Way.

Abstract

I report the discovery of two new Galactic Wolf-Rayet stars in Circinus via detection of their C, N and He Near-Infrared emission lines, using ESO-NTT-SOFI archival data. The H- and K-band spectra of WR67a and WR67b, indicate that they are Wolf-Rayet stars of WN6h and WC8 sub-types, respectively. WR67a presents a weak-lined spectrum probably reminiscent of young hydrogen rich main-sequence stars such as WR25 in Car OB1 and HD97950 in NGC3603. Indeed, this conclusion is reinforced by the close morphological match of the WR67a H- and K-band spectra with that for WR21a, a known extremely massive binary system. WR67b is probably a non-dusty WC8 Wolf-Rayet star that has a estimated heliocentric distance of 2.7(0.9) kpc, which for its Galactic coordinates, puts the star probably in the near portion of the Scutum-Centaurus arm.