Chromospheric activity Proxima Centauri

In this work we present Echelle spectra of the dM5.5e flare star Proxima Centauri, obtained in the CASLEO observatory. We have 44 observations from 1999 to date, taken in 11 different observing runs, which were flux calibrated. The index mostly used to measure stellar activity is the one combining Ca II H&K line fluxes. These lines, which axe formed in the stellar chromosphere, axe not particularly adequate to study cool stars, which axe intrinsically faint and red. We construct an index from H, which shows a good correlation with the Ca II lines and is more suitable for this cool star, due to its longer wavelength. We found that the He I D-3 line can be a useful proxy to discriminate the average chromospheric activity from the frequent flaring activity. We could separate this transient activity using this index, and we found that the remaining variability is compatible with the existence of an activity cycle of around 1300 days as suggested in previous works.