1,314 research outputs found
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&
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