Mass Transfer Variations in UX Monocerotis: Eight Years of Automated Photometric Monitoring We analyze eight years (1999-2007) of automated photometric observationsof the active Algol binary UX Monocerotis to search for mass transferbursts similar to those seen in U Cephei. The largest photometricanomaly is the mean gainer luminosity difference between thestream-impact hemisphere and the opposite hemisphere. We find an updatedWilson-Devinney solution for earlier six-color observations. The UX Mondonor star fills its Roche lobe and the gainer nearly fills itsrotational lobe. Instead of isolated bursts of the U Cep type, we foundnearly continuous brightness fluctuations likely produced by variablemass transfer. We discuss implications for mass transfer.
