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(Abridged) Most stellar activity cycles similar to that found in the Sun havebeen detected by using the chromospheric Ca II H&K lines as stellar activityproxies. However, it is unclear if such activity cycles could be identifiedusing other optical lines. Aims. To detect activity cycles in solar-analogstars and determine if these can be identified through other optical lines,such as Fe II and Balmer lines. We study the solar-analog star HD 45184.Methods. We analyse the activity signatures of HD 45184 by using 291 HARPSspectra obtained between 2003 and 2014. In order to search for line-core fluxesvariations, we focus on Ca II H&K and Balmer H$\alpha$, H$\beta$ lines, whichare usually used as optical chromospheric activity indicators. We calculate theHARPS-S index from Ca II H&K lines and convert it to the Mount-Wilson scale. Inaddition, we also consider as activity indicators the equivalent widths ofBalmer lines. Moreover, we analyse the possible variability of Fe II and othermetallic lines in the optical spectra. Results. We report for the first time along-term 5.14-yr activity cycle in the solar-analog star HD 45184. This makesHD 45184 one of most similar stars to the Sun with known activity cycle. Suchvariation is also evident in the first lines of the Balmer series, which notalways show a correlation with activity in solar-type stars. Notably, unlikethe solar case, we also found that the equivalent widths of the highphotospheric Fe II lines (4924 \AA, 5018 {\AA} and 5169 \AA) are modulated($\pm$ 2 m\AA) by the chromospheric cycle of the star. From short-termmodulation of the S index we calculate a rotational period of 19.98 days, whichagrees with its mean chromospheric activity level.

Discovery of an activity cycle in the solar-analog HD 45184. Exploring Balmer and metallic lines as activity proxy candidates