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
Published: 2025/10/2
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.