Photometry of symbiotic stars in the UBVRJHKLMN system

The photometry of AX Per AG Dra, BF Cyg, V443 Her and YY Her ispresented. Observations did not reveal any variations of infrared brightness greater than 0sup(m).3 for these stars. At the same time considerable (ΔU>1sup(m)) changes in the ultraviolet radiation of AX Per and AG Dra were noticed. Physical parameters of the individual components (hot star, cold star and ionized gas) of the systems AX per, AG Dra and BF Cyg are estimated. The presence of variations of optical brightness of AX Per and AG Dra during the time period of less than two years results in compact (< or approximately 5x1013 cm) sizes of gas envelopes mainly contributing to the recombination radiation. Their density exceeds 109 cm-3 and their mass is less than 5x10-7 Msub(S), where Msub(S) - the Sun mass. Radioobservations of BF Cyg having the same large envelope as AX Per show that the mass of the whole envelope observed optically is < 2x10-5. The classification of the red giants AX Per, AG Dra and BF Cyd according to a colour index (R-J)sub(x) agrees rather well with the classification according to optical spectra