Solar faculae and floccules: spectropolarimetric and filter observations in Fe I, Ba II, and Ca II lines
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| 1Kostik, RI 1Main Astronomical Observatory of the National Academy of Sciences of Ukraine, Kyiv, Ukraine |
| Kinemat. fiz. nebesnyh tel (Online) 2024, 40(1):65-74 |
| https://doi.org/10.15407/kfnt2024.01.065 |
| Language: Ukrainian |
Abstract: The results of spectropolarimetric and filter observations of a facula region located near the solar disc center in the lines of Fe I 1564.3 nm, Fe I 1565.8 nm, Ba II 455.4 nm and Ca II H 396.8 nm are discussed. The observations were obtained at the German Vacuum Tower Telescope of the Observatorio del Teide (Tenerife, Spain). Observations of the faculae region were obtained simultaneously in three spectral regions: spectropolarimetric observations of I, Q, U, V Stokes parameters of two lines of neutral iron Fe I 1564.8 nm and Fe I 1565.2 nm with a time resolution of 6 minutes 50 seconds; filter observations in 37 sections of the profile of the line of ionized barium Ba II 455.4 nm with a time resolution of 25.6 seconds; filter observations only in the center of the line of ionized calcium Ca II H 396.8 nm with a time resolution of 4.9 seconds. For the investigations we used the following observational values: 1) the power of the magnetic field at the height of the formation of a continuous spectrum near Fe I 1564.8 nm and Fe I 1565.2 nm (h ≈ –100 km) lines; 2) wave velocities at 14 heights in the atmosphere of the Sun, where radiation in Ba II 455.4 nm spectral line is formed (h ≈ 0...650 km) and calculated phase shifts between velocity fluctuations V in the photosphere at the height of radiation formation in the center of this line (h = 650 km) and velocity fluctuations at the other 13 heights; 3) the facula contrast at the height of the formation Ca II H 396.8 nm line center (h ≈ 1600 km). It is shown that: 1) the power of velocity oscillations, depending on the frequency of oscillations, varies greatly with the height in the atmosphere of the Sun. At the heights from 0 to 300 km the maximum oscillation power occurs at a frequency of 3.5 mHz. At the height of h = 650 km another maximum occurs near the frequency of 4.5 mHz, and at height of h = 1600 km the maximum oscillation power at a frequency near 1.5 mHz is quite noticeable. 2) The contrast in the center of the line Ca II H 396.8 nm (h = 650 km) does not monotonically increase with the increasing of the intensity of the photospheric magnetic field, as might be expected from general considerations. At large magnetic fields (B > 140 mT) this dependence becomes inverse. |
| Keywords: faculae, magnetic fields, oscillations, spectropolarimetric observations, Sun |
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