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Journal of Physical Studies 21(1/2), Article 1901 [4 pages] (2017)
DOI: https://doi.org/10.30970/jps.21.1901 KYIV MONITORING PROGRAM OF FRAUNHOFER LINES VARIATION WITH 11-YEAR CYCLE OF SOLAR ACTIVITYS. N. Osipov, R. I. Kostik, N. G. Shchukina
Main Astronomical Observatory, NAS of Ukraine, |
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The monitoring program of long-term variation of selected Fraunhofer lines is described. The aim of the program is to study how the physical parameters of the quiet solar atmosphere change over the solar cycle No.\,24. The research is based on high spectral resolution observations of the quiet Sun using the horizontal solar telescope ATSU-5 of the Main Astronomical Observatory of the National Academy of Sciences of Ukraine. The diagnostics of the solar cycle atmospheric variation includes observations of the \Halpha, \CaIIKH\ and about 40 spectral lines of neutral and ionized chemical elements at different positions on the solar disk. Since 2012 the observations are performed daily, when the weather conditions allow. The observational season lasts from March to October. The first results of the observations show that the line core depths and full widths at half maximum of the weak FeI 538.634 nm, moderate FeI 539.829 nm, and strong FeI 558.677 nm lines, as well as the bisector curvature of the last two lines show response to the cycle modulation of the total unsigned magnetic field of the Sun. The behavior of these line parameters can be explained by variations of the temperature and convective motions of the quiet photosphere during this cycle.
PACS number(s): 95.55.Qf, 95.75.-z, 95.75.Fg, 95.85.Kr, 96.60.Mz, 96.50.Wx