Simultaneous Studies of Two W UMa Systems in the UV and X-Ray

Simultaneous observations of two W UMa systems involving IUE and GINGA are proposed. These observations are intended to study the relationship between the transition regions and coronae of 44i Boo and VW Cep with simultaneous coverage in the UV and the 1 to 30 keV X-ray band. Monitoring of both systems will extend over several 8 hr. orbital periods in order to unambiguously separate orbital modulations from transient events. These observations will permit the study of both types of variability over a range of plasma temperatures and contribute to our understanding of coronal heating.