Rapid Spectral Variability of T Corona Borealis

The results of the analysis of photometric and spectral monitorings of the recurrent symbiotic nova T CrB, carried out using the low-resolution spectrograph TDS of the 2.5-m telescope and the CCD photometer of the 0.6-m telescope of the CMO SAI, are presented. It is shown that the fluxes in the emission lines H\(\alpha\), H\(\beta\), He I \(\lambda\) 5876 change by 6–16\(\%\), and in the emission line He II \(\lambda\) 4686 by about 60\(\%\) on timescales of 20–60 minutes. The line flux curves on August 25, 2020 are similar to the \(B\) light curve of T CrB, but with a time delay of up to 600 s for different lines. The observed spectrum is approximated by the radiation of the system components with the following parameters: a red giant of spectral type M4 III, a nebula with \(T_{e}=10^{4}\) K and emission measure of \(4\times 10^{58}\) cm\({}^{-3}\), and the accretion disk with \(R_{1}=0.003R_{\odot}\), \(R_{\textrm{out}}\approx 1R_{\odot}\) (at inclination \(i=57^{\circ}\)).