Faculty Sponsor

Bruce Hrivnak


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Arts and Sciences


Physics and Astronomy

Presentation Type

Poster Presentation

Symposium Date

Summer 7-24-2020


Our research revolved around analyzing how the brightness of proto-planetary nebulae (PPNe) vary over time. The overall goal was to analyze their light curves for periodicity and to find what the periods are. PPNe are celestial objects in transition from the red giant phase to the planetary nebula phase of a star’s life cycle, a phase that only lasts a few thousand years. PPNe are known to pulsate, causing them to periodically vary in brightness, and these pulsations can be observed and analyzed in their light curves. To analyze our PPNe for periodicity, we gathered data from the online database of a sky survey named ASAS-SN, which surveys the skies every clear night. The observational data stretch back to 2016. After reducing the data, we analyzed it using a program called Period04, which uses a Fourier transform to search for periods and allowed us to fit sine curves to the data. We studied a sample of 14 PPNe located in the southern hemisphere. We found that most have periods ranging from around 20 - 103 days, with several PPNe having multiple periods. The general pattern was that most of those PPNe have two periods that are within 10% of each other, forming beat periods in the amplitudes. Two PPNe also have longer period modulations of 1000 to 2000 days. This research was supported by a grant from the Indiana Space Grant Consortium.