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arXiv · 1908.05023

The chemical compositions of the 2 new HgMn stars HD 30085 and HD 30963. Comparison to $\chi$ Lupi A, $\nu$ Cap and HD 174567

R. Monier·E. Griffin·M. Gebran·T. Kilicoglu·T. Merle·F. Royer
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Abstract

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 chi Lupi A (B9 IV HgMn). In the spectra of HD 30085, HD 30963, the Hg II line at 3984 A line 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, and zirconium, barium, platinum and mercury and underabundances of helium, magnesium, scandium, nickel. The surface abundances of chi 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 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 2 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.

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R. Monier, E. Griffin, M. Gebran, T. Kilicoglu, T. Merle, F. Royer. 2019-08-14. The chemical compositions of the 2 new HgMn stars HD 30085 and HD 30963. Comparison to $\chi$ Lupi A, $\nu$ Cap and HD 174567. https://doi.org/10.3847/1538-3881/ab3b59

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