JWST/MIRI detection of [Ne V], [Ne VI], and [O IV] wind emission in the O9V star 10 Lacertae

TL;DR

This paper reports the detection of high-ionization wind emission lines in the mid-infrared spectra of the O9 V star 10 Lacertae using JWST/MIRI, revealing a hot wind component that suggests a higher mass-loss rate than previously estimated.

Contribution

First detection of [Ne V], [Ne VI], and [O IV] wind emission lines in an O star, indicating a hot wind component and revising mass-loss rate estimates.

Findings

Detected broad, flat-topped emission lines of high ions.

Revised mass-loss rate significantly higher than previous estimates.

Hot wind component helps resolve the 'weak wind' problem.

Abstract

We report the detection of broad, flat-topped emission in the fine-structure lines of [Ne V], [Ne VI], and [O IV] in mid-infrared spectra of the O9 V star 10 Lacertae obtained with JWST/MIRI. Optically thin emission in these high ions traces a hot, low-density component of the wind. The observed line fluxes imply a mass-loss rate of > 3 x 10^8 Msun/yr, which is an order of magnitude larger than previous estimates based on UV and optical diagnostics. The presence of this hot component reconciles measured values of the mass-loss rate with theoretical predictions, and appears to solve the "weak wind" problem for the particular case of 10 Lac.