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96 - J. Kubat , S. M. Saad , A. Kawka 2010
We studied both components of a slightly overlooked visual binary HR 1847 spectroscopically to determine its basic physical and orbital parameters. Basic stellar parameters were determined by comparing synthetic spectra to the observed echelle spectr a, which cover both the optical and near-IR regions. New observations of this system used the Ondv{r}ejov and Rozhen 2-m telescopes and their coude spectrographs. Radial velocities from individual spectra were measured and then analysed with the code {FOTEL} to determine orbital parameters. The spectroscopic orbit of HR 1847A is presented for the first time. It is a single-lined spectroscopic binary with a B-type primary, a period of 719.79 days, and a highly eccentric orbit with e=0.7. We confirmed that HR 1847B is a Be star. Its Halpha emission significantly decreased from 2003 to 2008. Both components have a spectral type B7-8 and luminosity class IV-V.
We verify the nature of emission-line stars in the field of the open cluster NGC 6910. % Spectroscopy in the H-alpha region was obtained. Raw CCD frames of spectra of all stars fainter than V = 9 mag observed by us are significantly affected by nebul ar emission originating in the surrounding HII region IC 1318. After careful data reduction and subtraction of the nebular radiation we succeeded in obtaining reliable stellar spectra. We confirm that the star NGC 6910 37 is a Be star, and we have corrected the classification of V1973 Cyg from an Ae star to a normal A type star. Since the diffuse interstellar bands do not appear in the spectrum of this star while being present in the other stars we observed, we confirm that V1973 Cyg is a foreground object with respect to IC 1318 and NGC 6910. We also find that the H-alpha line in HD 194279 has a P Cygni profile and the H-alpha line profile is variable in HD 229196.
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