Detecting prolonged activity minima in binary stars

Context. It is well known that from 1645 to 1715 solar activity was notably low and the number of sunspots extremely reduced. This epoch as Maunder Minimum (MM). The study stars in prolonged minima like MM could help shed light on this enigmatic epoch. Aims. To explore if star $\zeta^{2}$ Ret, which belongs a binary system, state similar MM. We have collected more than 430 spectra acquired between 2000 2019 with HARPS, REOSC, UVES, FEROS spectrographs. Methods. performed detailed long-term both components using Mount Wilson index, obtained Ca II H\&K lines. search for signs an cycle, we analyzed resulting time-series Generalized Lomb-Scargle CLEAN periodograms. Results. Our spectroscopic analysis shows high level zet01 Ret significant decrease magnetic cycle amplitude Ret. Thus, difference has been slightly increased ($\Delta$log (RHK) $\sim$0.24 dex), when compared previously reported value. long series here allowed us recalculate constrain period $\sim$7.9 yr. also detected $\sim$4.2 yr $\zeta^{1}$ Conclusions. By analogy scenario proposes weak during MM, suggest signatures showed by i.e., very its stellar companion, decreasing ($\sim$47%), cyclic behaviour, are possible evidence be state. is, our knowledge, first candidate through highly discrepant behaviour system.