BV photometry of UX ARIETIS

Abstract

Differential BV photometry of UX Ari obtained on 58 nights during 1984-1985, 1985-1986, 1986-1987, and 1987-1988 observing season is presented. It is found that (B-V) is phase dependent, with the system being reddest at the light maximum. This is interpreted as being due to the variable fractional contribution by the G5 V component to the total light at shorter wavelengths. An analysis of the available data indicates that, at larger amplitudes of the photometric wave, the brightness at maximum increases and that at minimum decreases, and both converge to DeltaV of about 1.0 mag at very low amplitudes. It implies that the low wave amplitudes are essentially due to more homogeneity in the surface distribution of spots rather than to low levels of spot activity. The variation in wave amplitude is found to be near-sinusoidal with a period around 13-14 years.