CCD PHOTOMETRY OF THE ECLIPSING BINARY RU UMI

We present a new high-precision R-band light curve of the eclipsing binary RU UMi. These observations have been obtained with a new CCD camera system on the 0.95-m James Gregory Telescope in St Andrews. This equipment and the associated reduction software is described. Light-curve analyses indicate that a mass ratio in the range of 0.34-0.40 is probable. On this basis, it would appear that a mass transfer event has taken place and that RU UMi is presently in a detached configuration and consists of an apparently main-sequence FOV star and a K2-5 star which is both overluminous and oversized for its mass.