Updating Analyses 6 Proto-Planetary Nebulae

Faculty Sponsor

Bruce Hrivnak


Arts and Sciences


Physics and Astronomy

Presentation Type

Poster Presentation

Symposium Date

Summer 7-23-2021


My research was conducted on proto-planetary nebulae and attempted to find one or multiple periods to their brightness. Proto-Planetary Nebulae (PPNe) are stars late in their evolution in transition between the second red giant phase and the planetary nebulae phase. They are known to pulsate, and some have been found to have multiple periods to their pulsation. The goal of this research is to find these periods so that we may better understand the internal properties of PPNe. I conducted my research under the guidance of Professor Bruce Hrivnak. The six stars I researched have been previously studied by him and documented in his paper Variability in Proto-Planetary Nebulae I. Light Curve Studies of 12 Carbon-Rich Objects (Hrivnak et al. 2010). I have updated the analyses of these stars using new data from the All-Sky Automated Survey for Supernovae in addition to the Valparaiso University Observatory. To analyze my PPNe candidates, I studied their light curves (brightness over time) using a period searching program called Period04. The stars I have researched show cyclical variability with at least one period associated with it. A few of my stars indicate two different periods with patterns of constructive and destructive interference. The periods for my stars range between 80 and 160 days. None of my stars have shown evidence for long-term (multi-year) periods. Long-term periods have been observed in some PPNe and are thought not to be associated with pulsation but possibly with binarity. This research is supported by an NSF REU grant.

Biographical Information about Author(s)

Peyton Grimm is a rising Junior in the Department of Physics and Astronomy. He is majoring in Physics and Computer Science and minoring in Mathematics. Peyton Grimm has been working under Professor Hrivnak for this summer and the summer prior. He is conducting this research with Sean Egan, Will Bakke, and Andrew Paxson.

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