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The Chemical Compositions of the Two New HgMn Stars HD 30085 and HD 30963: Comparison to χ Lupi A, ν Cap, and HD 174567

par Monier, Richard;Griffin, Elizabeth;Gebran, M.;Kilioǧlu, T.;Merle, Thibault ;Royer, Frédéric
Référence The Astronomical journal, 158, 4, 157
Publication Publié, 2019-06-01

Article révisé par les pairs

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Résumé :

We report on a detailed abundance study of the fairly bright slow rotators HD 30085 (A0 IV), HD 30963 (B9 III), and HD 174567 (A0 V), hitherto reported as normal stars and the sharp-lined χ Lupi A (B9 IV HgMn). In the spectra of HD 30085 and HD 30963, the Hg ii line at 3984 Å is conspicuous and numerous lines of silicon, manganese, chromium, titanium, iron, strontium, yttrium, and zirconium appear to be strong absorbers. A comparison of the mean spectra of HD 30085 and HD 30963 with a grid of synthetic spectra for selected unblended lines having reliable updated atomic data reveals large overabundances of phosphorus, titanium, chromium, manganese, strontium, yttrium, zirconium, barium, platinum, and mercury, and underabundances of helium, magnesium, scandium, and nickel. The surface abundances of χ Lupi A have been rederived on the same effective temperature scale and using the same atomic data for consistency and comparison for HD 30085 and HD 30963. For HD 174567, milder deficiencies and excesses are found. The abundances of sodium, magnesium, and calcium have been corrected for non-LTE (NLTE) effects. The effective temperatures, surface gravities, low projected rotational velocities, and the peculiar abundance patterns of HD 30085 and HD 30963 show that these stars are two new HgMn stars and should be reclassified as such. HD 174567 is most likely a new marginally chemically peculiar star. A list of the identifications of lines absorbing more than 2% in the spectrum of HD 30085 is also provided.