On the Overcontact Binary V2388 Oph and An Improved M–R Relation for Ltcbs

The evolutionary stage of the low-temperature contact binary (LTCB) V2388 Oph has been investigated. V2388 Oph was previously classified as an A-type W UMa star, and is the brighter member of the visual binary Fin 381. When compared to other well-known LTCBs it is evident that the primary component has evolved to the TAMS, and the companion also seems to be more evolved than a ZAMS star. Mochnacki proposed a new subgroup of W UMa stars, namely of OO Aql type, distinct from A and W types. V2388 Oph is suggested to be a member of this new group.