Methods to Test the Source of the Extreme Gas Motions in WS 35

TL;DR

This paper explores the possibility that a stellar wind, potentially a new metal-only wind regime, explains extreme gas motions in WS 35, proposing observational tests to distinguish wind models.

Contribution

It introduces the concept of a metal-only stellar wind as a novel explanation for high-velocity gas in WS 35 and discusses how future radio observations can test this hypothesis.

Findings

Proposes a super-Eddington wind model for WS 35.

Suggests radio spectral observations can differentiate wind types.

Highlights the potential of a new wind regime in stellar physics.

Abstract

We present theoretical arguments toward the plausibility of a stellar wind to explain the 16000 km s$^{-1}$ line broadening in the optical spectra of WS 35, the central star in the Pa 30 nebula. The wind model is discussed in the context of super-Eddington flows. We argue that WS 35 potentially occupies a new regime of wind driving theory as the first metal-only wind. While this framework provides a promising avenue for explaining the high speed flow, questions remain about the source's true nature. We further describe how future radio observations can provide an independent test of the spherical wind scenario. A magnetically channeled wind would likely produce a relatively flat and bright radio spectral energy distributions. By contrast a spherical wind should result in a thermal radio spectrum with a canonical continuum slope of $\nu^{0.6}$, and a brightness level consistent with the currently predicted mass-loss rate.