Long-Term Brightness Variation Study in Three Proto-Planetary Nebulae

Faculty Sponsor

Bruce Hrivnak


Arts and Sciences


Physics and Astronomy

Presentation Type

Poster Presentation

Symposium Date

Summer 7-31-2014


As stars like the Sun age, they go through various stages. Recently, a missing link was discovered between the Red Giant and Planetary Nebula phases, called Proto-Planetary Nebulae (PPNs). Throughout the summer, brightness measurements were taken for 25 PPNs. These measurements, combined with the data collected in the last 20 years, allow us to study the variations in brightness of these stars and look for specific periods in the light curves. By studying the brightness variations, we hope to better understand the internal structures of PPNs. The three PPNs we are studying for periodicity are 89 Her, IRAS 19114+002, and IRAS 20004+2955. In each of the three stars, we have determined one dominant period and one or two additional periods. These dominant periods range from 70 to 200 days. This is the culmination of a long-term project to monitor the light variations of these three stars. This research is supported by grants from the NSF and from NASA through the Indiana Space Grant Consortium.

Biographical Information about Author(s)

Stephen Freund is a junior physics major and Chris Morrissey is a pre-med sophomore physics major. After graduation, Stephen will attend graduate school for applied physics and Chris plans to attend either med school or graduate school.

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