Binary Type Definitions

Detached

A binary system where both stars are well within their inner Lagrangian surface.

Example System: KP Aql

Semi-detached

One of the stars of the binary completely fills its inner Lagrangian surface; also called Algol systems.

Example System: AD Her

Near contact

A semi-detached system where the other component is almost in contact with its inner Lagrangian surface.

Example System: V1010 Oph

Contact

System where both stars exactly fill their inner Lagrangian surface.

Example System: BX And

Overcontact

A binary system where both stars overfill their inner Lagrangian surface.

Example System: AE Phe

Double contact

A binary system where both stars are in contact with their inner Lagrangian surface and one or both stars are in asynchronous rotation.

Example System: RZ Sct