Some peculiarities of the variability of the positional and photometric line parameters in the spectrum of HD 93521. Differential rotation of the star |
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| Authors: | A Kh Rzaev |
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| Institution: | (1) Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnij Arkhyz, 369167, Russia;(2) Shamakha Astrophysical Observatory, National Academy of Sciences of Azerbaijan, Yu. Mamedaliev Settlement, 373243, Azerbaijan |
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| Abstract: | The variability of positional and photometric parameters of the lines in the spectrum of HD 93521 is analyzed using CCD spectra taken with the PFES echelle spectrograph of the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS). To study the velocity field of the star’s atmosphere, the radial velocity variations are measured separately for the blue and red halves of the absorption profile at different levels of residual line intensity. The amplitude and phase of temporal variations of radial velocity differ for the two halves of the absorption profile. In case of strong HeI, Hβ, andHα lines the amplitude depends on intensity r. The time scales (P) of radial velocity variations and the mean halfwidths \(\overline {FW H M} \) differ for different lines and correlate fairly well with their central depths. The increase of P and decrease of \(\overline {FW H M} \) from weak to strong lines are due to the differential nature of the rotation of the star. Our analysis proofs that HD 93521 is a run-away star and this fact explains its location at a distance of about 2.0 kpc above the Galactic plane. |
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