2022RNAAS...6...86M

The analysis of nine high resolution SWP spectra of the HgMn star χ Lupi obtained through the large aperture recorded by the International Ultraviolet Explorer reveals that the far-ultraviolet flux of χ Lupi remained probably constant over a timescale of about 24 hr, i.e., about 25% of the recently determined rotational period. Whereas eight spectra have levels consistent with the average spectrum, one spectrum shows a lower flux by about 15%. This probably reflects an instrumental effect, possibly a loss of the flux (the star may have slipped outside the aperture for a fraction of the exposure). The available IUE data do not rule out variations in the FUV flux.