The magnetic, spectroscopic, and photometric variability of the Wolf–Rayet star WR 55

Studies of magnetic fields in the most evolved massive stars, the Wolf–Rayet stars, are of special importance because they are progenitors of certain types of supernovae. The first detection of a magnetic field of the order of a few hundred gauss in the WN7 star WR 55, based on a few FORS2 low-resolution spectropolarimetric observations, was reported in 2020. In this work, we present new FORS2 observations allowing us to detect magnetic and spectroscopic variability with a period of 11.90 h. No significant frequencies were detected in TESS and ASAS-SN photometric observations. Importantly, magnetic field detections are achieved currently only in two Wolf–Rayet stars, WR 6 and WR 55, both showing the presence of corotating interacting regions.

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