The Study of Light Variability in a Sample of Proto-Planetary Nebulae

Primary Submission Contact

Abigail Vance

Faculty Sponsor

Bruce Hrivnak

Faculty Sponsor Email Address



Arts and Sciences


Department of Physics and Astronomy

Document Type

Poster Presentation


Fall 10-30-2015


We are studying the light variability of a subclass of evolved stars called proto-planetary nebulae. The proto-planetary nebulae phase is a stage near the end of the life cycle of stars like our sun as they evolve over time. Our goal is to determine the period of pulsation of each star, which can eventually be used to determine its size, mass, and density. Using the 0.4 meter telescope and CCD detector located at the VU observatory, our group took many images of these objects over the course of the summer on every clear night. These images add another season of data to this project which began at VU in 2008. The computer software Period04 was used to search for periods within the full data set spanning from 2008 to 2014. We have found periodicity in five of the ten stars assigned to us to analyze. These periods range from just a few days to as long as three years, some even had multiple periods, and in one case the first two periods have a ratio of 2:1. The periodicities in two stars show evidence for a binary companion. We will present some of the light curves and the initial period findings. This research was funded by the National Science Foundation through the MSEED Program, and grants to Professor Hrivnak from the National Science Foundation and from NASA through the Indiana Space Grant Consortium.

Biographical Information about Author(s)

The authors are both juniors in the Department of Physics and Astronomy. Both students have an interest in stellar astronomy and got interested in this particular topic upon hearing the research being done by Dr. Bruce Hrivnak. The research from the summer is being continued on into the school year.

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