We analyzed data from the massive binary star eta Carinae taken with the CTIO 1.5 m telescope and CHIRON spectrograph during the recent periastron passages. The variability of Hβ and Hα lines were examined beginning a short period before and through the entire duration of the 2020 periastron event. We have measured equivalent widths plots for these orbital phases and compare the last three events. The variability pattern reveals an overall decrease in line strength which reaches a minimum near periastron before increase slightly then flattening. Comparisons between successive periastron passages show that the line is decreasing in strength, consistent with the long-term variations that were recently discussed by Damineli et al. (2019).
This research was supported through both Embry-Riddle Aeronautical University’s Faculty Innovative Research in Science and Technology (FIRST) Program and HST-GO Programs 15611 and 15992.