Determination of the Abundance of Mercury from the Hg <scp>ii</scp> Line at 5677.10 Å. XVIII. HD 53929

Abstract The weak line of Hg ii located at 5677.10 Å is not detected in ESPaDOnS spectra of the HgMn star HD 53929. The Hg ii feature at 3983.93 Å commonly used to measure the abundance of mercury in HgMn star is present as a very weak feature. The low abundance excess of mercury partly explains why the intrinsically weaker transition at 5677.10 Å is not detected. Abundances of helium, magnesium, phosphorus, sulfur, titanium, chromium, manganese, iron are measured from the synthesis of the several spectral intervals. The new abundances derived here differ from previous determinations because different fundamental parameters, projected rotational velocity, lines and atomic data have been used in this work. Solar upper limits are found for the abundances of strontium, zirconium, yttrium and barium. Inspection of the recent Transiting Exoplanet Survey Satellite lightcurves of HD 53929 shows a complex pattern of variability which might combine rotational and pulsational variability.