Determination of the Abundance of Mercury from the Hg ii Line at 5677.10 Å in Late B-type Stars. XXVIII. HD 19400 ( θ Hyi)

Abstract The weak line of Hg ii located at 5677.10 Å is used to measure the mercury abundance in the late B-type star HD 19400 ( θ Hyi). This line is detected at 3 σ above the noise in the adjacent continuum. The synthesis of this line confirms a large overabundance of mercury, about +5.30 dex, which agrees very well with the excess derived from the other Hg ii line at 3983.93 Å. Spectrum synthesis yields estimates of the abundance deficiencies/excesses for 20 other elements. The following excesses/deficiencies are found: helium (−1.30 dex), carbon (−0.40), oxygen (−0.60), neon (0.00), magnesium (0.00), aluminium (−1.30), silicon (+0.48), phosphorus (+2.30), sulfur (−0.82), calcium (0.00), titanium (0.88), chromium (0.67), manganese (1.83), iron (0.85), gallium (3.00), strontium (+0.70), yttrium (0.60), zirconium (0.00), xenon (+5.00) and barium (+0.00). Most light elements are deficient (except for Si and P), the iron-peak elements are all overabundant, gallium and xenon are very overabundant.