OPTICAL POLARIMETRY AND DISTANCE ESTIMATE FOR NOVA CYGNI 1975

Polarization observations of Nova Cygni 1975 were obtained with several passbands in the wavelength interval AA 4600-6700 A before and after maximum light. Special attention was given to the regions of Ha and HjS emission. On average, a precision of ± 0-04 per cent polarization was obtained in these observations. Statistically significant evidence for the presence of an intrinsically-polarized component in the light from the nova is very weak, but such a component is not completely ruled out. Any variability, however, is likely to be less than 0*18 per cent polarization. The observed polarization (1-38 per cent at A 5460), is therefore attributed mainly to scattering in the interstellar medium and the amount of polarization is employed to give a rough estimate of the distance of the nova and its absolute magnitude at maximum brightness, namely 1*14 kpc and - iom*i. © Royal Astronomical Society.