ИСТИНА

Some types of eruptive prominences are closely related to solar flares and sometimes even form part of the flare process. When these objects are observed at the edge of the visible solar disk, they are very difficult to distinguish from each other. Only detailed spectral studies allow us to decide what we have observed, a prominence or a flare. We present an analysis of the event that occurred on the eastern limb on April 21, 2015 at 13:05–13:58 UT, which was observed by a horizontal telescope and a spectrograph (Ondřejov observatory). The studied eruption of a strongly curved prominence was preceded by a limb flare in the same active re-gion starting at 10:30 UT. The eruption of a strongly curved prominence was accompanied by the appearance of a soft X-ray source and strong heating of the prominence plasma. The pur-pose of this work is to study the behavior of the emission intensity curves in the H CaII, Hβ, D3, Hα, and Ca IR 8542 Å lines during the development of the prominence and compare the results with calculated values. Calculations are performed in the lines of hydrogen, the CaII ion, and the helium atom, taking into account the main processes that determine the radiation of an opaque gas in spectral lines. The results are discussed.