Elemental Abundance Analysis of Single and Binary Late-B Stars Using Sub-meter Class Telescopes: HR 342, HR 769, HR 1284, and HR 8705

We test the capabilities of 0.4 m telescopes equipped with an \'{e}chelle spectrograph to derive fundamental parameters and elemental abundances of four late-B type stars: HR 342, HR 769, HR 1284, and HR 8705. The medium resolution (R~14000) spectra covering the wavelength range of 4380-7350 {\AA} of the four stars have been obtained using the 40-cm-telescope in Ankara University Kreiken Observatory (AUKR). Using spectrum synthesis, we were able to derive the abundances of eleven chemical elements. We find that these stars do not show remarkable departures from the solar abundances, except for HR 8705 and the primary component of HR 1284, which exhibit slight underabundances of a few elements, i.e., O, Mg, Al, Si, and Fe. We also find that HR 1284 is probably a new spectroscopic binary star. In order to model the spectrum of this object, one of us (TK) has developed a new graphic interface which allows us to synthesize the composite spectrum of binary stars.Comment: 3 pages, 2 figures and 1 table. Accepted proceeding of the Observing techniques, instrumentation and science for metre-class telescopes II conference, September 24-28, 2018, Tatransk\'a Lomnica, Slovaki

Four new HgMn stars: HD 18104, HD 30085, HD 32867, HD 53588

We have detected four new HgMn stars, while monitoring a sample of apparently slowly rotating superficially normal bright late B and early A stars in the northern hemisphere. Important classification lines of Hg II and Mn II are found as conspicuous features in the high resolution SOPHIE spectra of these stars (R = 75000). Several lines of Hg II, Mn II and Fe II have been synthesized using model atmospheres and the spectrum synthesis code SYNSPEC48 including hyperfine structure of various isotopes when relevant. These synthetic spectra have been compared to high resolution high signal-to-noise observations of these stars in order to derive abundances of these key elements. The four stars are found to have distinct enhancements of Hg and Mn which show that these stars are not superficially normal B and A stars, but actually are new HgMn stars and should reclassified as such.Comment: 4 pages, 3 figures, accepted in A&