CK Aqr time keeping. Evidence for a ternary [Observed: 2005-20]
Photometric measurements of the contact binary system CK Aqr are presented. 49 times of minimum were obtained between 2005 and 2020. Along with already published observations, this allows the derivation of an improved ephemeris. The resulting O-C diagram shows oscillations which are interpreted as the light time travel effect due to a third component, with a period of 8.2 years.