2022RNAAS...6...93M

The analysis of high resolution SWP spectra of the HgMn stars HD 27295 (53 Tau) and HD 33548 obtained through the large aperture recorded by the International Ultraviolet Explorer reveals that the far ultraviolet flux of these two stars remained constant over the various observations with IUE. The TESS lightcurves of 53 Tau show a periodic sine structure with a period estimated to be around 4.43 days whereas that of HD 35548 do not show evidence for periodic variability. The absence of far and mid-UV variability of these two stars precludes the presence of large chemical gradients over their surfaces at the time of the IUE observations.