ИСТИНА

We propose a model of the spherically symmetric circumstellar dust shell of a carbon Mira star V CrB which reproduces the observed SED fairly well at both moments of minimum and maximum brightness. The dust envelope is characterized by the following parameters: the optical depth τK=0.33, the radius of spherical dust grains agr=0.5 m, the mass ratio of carbon and SiC dust particles is 2, the position of the inner edge of the shell Rin=8 au. Our estimation of the minimum distance between the star and the outer edge of the shell is 40000 au. The effective temperature of the star adapted in this work at the different phases of pulsations is 3000 K and 2400 K at the moments of maximum and minimum brightness respectively. The corresponding bolometric fluxes estimated from the observational data are Fbol.max=5.13*e-7 erg*cm-2s-1 and Fbol.min=2.64*e-7 erg*cm-2s-1. In order to reduce the observational data to the same moment of time the analysis of the star variability was conducted. The period of the brightness variations appears to be 355.2 days in the JHKLM bands and 352 days in the B and V bands. In addition to the periodic pulsations, the JHK magnitudes show sinusoidal changes in the average level of brightness with a characteristic period of ~8300 days.