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arXiv · 2510.02615

Evolutionary Map of the Universe: Detection of the Wolf-Rayet Star WR40

A. C. Bradley·Z. J. Smeaton·M. D. Filipovic·N. F. H. Tothill·R. Z. E. Alsaberi·J. D. Collier·Y. A. Gordon·A. M. Hopkins·H. Zakir
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Abstract

We present a radio-continuum detection of the well-known Wolf-Rayet star WR40 at 943.5 MHz using observations from the EMU survey. We find that the shell surrounding WR40, known as RCW 58, has a flux density of 158.9+/-15.8 mJy and the star itself is 0.41+/-0.04 mJy. The shell size is found to be 9' x 6', which matches well with the shell in Halpha and is similarly matched to the shell at 22 um in infrared. Using Gaia data, we derive a linear size of 7.32(+/-0.34) x 4.89(+/-0.23) pc at a distance of 2.79+/-0.13 kpc. We use previous ATCA observations at 8.64, 4.80, and 2.4 GHz to determine a spectral index of WR40, which is estimated to be alpha = 0.80+/-0.11, indicating that the emission from the star is thermal.

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A. C. Bradley, Z. J. Smeaton, M. D. Filipovic, N. F. H. Tothill, R. Z. E. Alsaberi, J. D. Collier, Y. A. Gordon, A. M. Hopkins, H. Zakir. 2025-10-02. Evolutionary Map of the Universe: Detection of the Wolf-Rayet Star WR40. https://arxiv.org/abs/2510.02615

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