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A new study of orbital and long-term variations of the Be star phi Persei
Jonák, Juraj ; Harmanec, Petr (advisor) ; Krtička, Jiří (referee)
The well-known spectroscopic binary ϕ Per is a peculiar compact system, composed of a Be star with an O-type subdwarf companion. A set of nearly 400 spectra in the red and blue regions from Ondřejov and Potsdam Observatories as well as spectra published in the BeSS database were examined. From the radial velocities of Hα, Hβ, and Hγ emission lines and FUV observations from the IUE and HST, a new precise ephemeris was determined. The revised values of M sin3 (i) are 11.84 and 1.48 M (with uncertainties of 0.64 and 0.09 M ), re- spectively, for the primary and secondary. In addition, the system shows cyclic variations (with a time scale of about 5 years) in the profiles of Balmer lines, manifested in their radial velocities, central intensities and V/R ratios. Understanding complex stellar systems requires combining multiple types of ob- servations and creating models of sufficient complexity. In our case, a combination of interferometric visibilities from the CHARA/VEGA array, spectral energy dis- tribution as well as individual spectral lines were used. Radiative-transfer compu- tations were performed with the program PYSHELLSPEC, and physical parameters of the ϕ Per primary and the surrounding disc were derived. They correspond to an evolved system, in which most of mass was transferred from the secondary to...
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A new spectroscopic study of the eclipsing binary V1143 Cyg
Jonák, Juraj ; Harmanec, Petr (advisor) ; Wolf, Marek (referee)
Using multiple red spectra of the eclipsing binary V1143 Cyg obtained between the years 2015 and 2017 at the Observatory of Ondřejov and in 2008 and 2009 at the Lick observatory in USA, we calculated a more recent orbital solution using the method of Fourier spectra disentangling. These new data, in addition to previous spectroscopic and photometric measurements, span an observation period of almost a hundred years. Since this binary star is remarkable due to its high orbital excentricity, along with classical, a significant relativistic apsidal motion is present. Using the software PHOEBE and available data we calculated the value of the total apsidal motion as 9,8(3).10−5 deg.d−1 , which is in good agreement with previous works. 1
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