RZ Ophiuchi: photometric variations and a detached configuration

A nine-year survey of multicolor intermediate-band photometry of RZ Oph reveals small but significant brightness-change variations outside primary eclipse. Most of these changes cannot be explained by the ellipticity effect of a cool mass losing component which fills its Roche lobe. Instead, this evidence supports recent analyses that have proposed a detached configuration for this binary. Photometric and spectroscopic observations point to the existence of a large accretion disk around the hot mass-gaining star in this binary, implying that mass transfer occurs in this system by some process other than Roche lobe overflow.