The Discovery of Three Galactic Wolf-Rayet Stars

TL;DR

This paper reports the discovery of three new Galactic Wolf-Rayet stars using Gaia spectra and ground-based spectroscopy, revealing the incompleteness of current WR catalogs and emphasizing the potential for future discoveries.

Contribution

It introduces a method leveraging Gaia low-dispersion spectra to identify previously unrecognized Wolf-Rayet stars in the Milky Way.

Findings

Discovered three new Galactic Wolf-Rayet stars.

Two are WC9 types, one is a WN6 + O6.5 V binary.

Highlights the potential for future WR discoveries using Gaia data.

Abstract

Wolf-Rayet stars (WRs) are evolved massive stars in the brief stage before they undergo core collapse. Not only are they rare, but they also can be particularly difficult to find due to the high extinction in the Galactic plane. This paper discusses the discovery of three new Galactic WRs previously classified as H$\alpha$ emission stars, but thanks to Gaia spectra, we were able to identify the broad, strong emission lines that characterize WRs. Using the Lowell Discovery Telescope and the DeVeny spectrograph, we obtained spectra for each star. Two are WC9s, and the third is a WN6 + O6.5 V binary. The latter is a known eclipsing system with a 4.4 day period from ASAS-SN data. We calculate absolute visual magnitudes for all three stars to be between -7 and -6, which is consistent with our expectations of these subtypes. These discoveries highlight the incompleteness of the WR census in our local volume of the Milky Way and suggest the potential for future Galactic WR discoveries from Gaia low-dispersion spectra. Furthermore, radial velocity studies of the newly found binary will provide direct mass estimates and orbital parameters, adding to our knowledge of the role that binarity plays in massive star evolution.