UV Cas: Photometry, polarization, and spectrum near maximum light

The UBV observations of UV Gas during 1996-1999 show mostly irregular light variations. The VB light variations on time scales from one day to two wee ks have a smaller amplitude than those on longer time scales. The amplitude of the UBV light variations on time scales from 20 to 200 days reaches 0.( m)4, 0.(m)3, and 0.(m)2, respectively. The colors of UV Gas do not correspo nd to G5 supergiants, but are more similar to the colors of GO I stars at s ubstantial U-B color excesses. A. comparison of the energy distribution for UV Gas, as constructed from the broadband UBVRI observations in 1982, with the energy distribution for GO supergiants reveals enhanced near-infrared and ultraviolet emission, which can be attributed to unusual chemical compo sition of the star. The polarization of light from UV Cas in quiescence is mainly interstellar in origin, although the presence of weak intrinsic pola rization produced by the gas-dust circumstellar medium cannot be ruled out either. The strength of C I lines in the spectrum of UV Cas confirms that i t belongs to R CrB stars, as well as the conclusion of Orlov and Rodriguez that carbon is appreciably overabundant. The atmospheric metal underabundan ce in UV Cas may be larger than has been thought previously. The line broad ening is sigma = 10.7 km s(-1) The star's effective temperature appears to be higher than 5500 K. The radial velocity of UV Cas measured from metal an d carbon lines is -31.17 +/- 0.38 km s(-1). The Na I D lines have a split p rofile, with the two absorbing clouds observed toward UV Cas at distances < 1 kpc and 1.5-2.5 kpc from the Sun contributing to its components. (C) 200 0 MAIK "Nauka/Interperiodica".