We intensively studied the flare activity on the stellar object KIC011764567 .
The star was thought to be solar type , with a temperature of T _ { eff } \approx ( 5640 \pm 200 ) \ > K , \log ( g ) = ( 4.3 \pm 0.3 ) \ > dex and a rotational period of P _ { rot } \approx 22 \ > d ( Brown et al . 2011 ) .
High resolution spectra turn the target to an evolved object with T _ { eff } = ( 5300 \pm 150 ) \ > K , a metalicity of { [ m / H ] } = ( -0.5 \pm 0.2 ) , a surface gravity of \log ( g ) = ( 3.3 \pm 0.4 ) \ > dex , and a projected rotational velocity of v \sin i = ( 22 \pm 1 ) \ > km s ^ { -1 } .
Within an observing time span of 4 years we detected 150 flares in Kepler data in an energy range of 10 ^ { 36 } -10 ^ { 37 } \ > erg .
From a dynamical Lomb-Scargle periodogram we have evidence for differential rotation as well as for stellar spot evolution and migration .
Analysing the occurrence times of the flares we found hints for a periodic flare frequency cycle of 430 - 460 \ > d , the significance increases with an increasing threshold of the flares equivalent duration .
One explanation is a very short activity cycle of the star with that period .
Another possibility , also proposed by others in similar cases , is that the larger flares may be triggered by external phenomena , such as magnetically interaction with an unseen companion .
Our high resolution spectra show that KIC011764567 is not a short period binary star .