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

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.

arXiv comment68 pages, accepted for publication in The Astronomical Journal

References in corpus (11)

• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• A Stellar Rotation Census of B Stars: from ZAMS to TAMS
• POLLUX : a database of synthetic stellar spectra
• Improved Laboratory Transition Probabilities for Ce II, Application to the Cerium Abundances of the Sun and Five r-process Rich, Metal-Poor Stars, and Rare Earth Lab Data
• Improved Laboratory Transition Probabilities for Er II and Applications to the Erbium Abundances of the Sun and Five r-Process Rich, Metal-Poor Stars
• Rare-earth elements in the atmosphere of the magnetic chemically peculiar star HD 144897. New classification of the Nd III spectrum
• Improved V II log($gf$) Values, Hyperfine Structure Constants, and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937
• Pulsation tomography of rapidly oscillating Ap stars. Resolving the third dimension in peculiar pulsating stellar atmospheres
• Normal A0--A1 stars with low rotational velocities. I. Abundance determination and classification
• Four new HgMn stars: HD 18104, HD 30085, HD 32867, HD 53588
• HR 8844: a new transition object between the Am stars and the HgMn stars ?

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