# The Evolutionary Status of WN3/O3 Wolf-Rayet Stars

## TL;DR

This paper reports the discovery of a new type of Wolf-Rayet star with unique spectral features and discusses their possible evolutionary origins, suggesting they may form in low-metallicity environments and are linked to gamma-ray bursts.

## Contribution

It introduces a new class of Wolf-Rayet stars with unusual spectral and physical properties, challenging existing evolutionary models.

## Key findings

- Stars have lower mass-loss rates than typical WN3 stars.
- They retain significant hydrogen and show CNO-equilibrium nitrogen levels.
- Their evolutionary path likely differs from quasi-homogeneous evolution.

## Abstract

As part of a multi-year survey for Wolf-Rayet stars in the Magellanic Clouds, we have discovered a new type of Wolf-Rayet star with both strong emission and absorption. While one might initially classify these stars as WN3+O3V binaries based on their spectra, such a pairing is unlikely given their faint visual magnitudes. Spectral modeling suggests effective temperatures and bolometric luminosities similar to those of other early-type LMC WNs but with mass-loss rates that are three to five times lower than expected. They additionally retain a significant amount of hydrogen, with nitrogen at its CNO-equilibrium value (10x enhanced). Their evolutionary status remains an open question. Here we discuss why these stars did not evolve through quasi-homogeneous evolution. Instead we suggest that based on a link with long-duration gamma ray bursts, they may form in lower metallicity environments. A new survey in M33, which has a large metallicity gradient, is underway.