Exploring Close Binary Stars in Planetary Nebulae Using the PHOEBE Modeling Software

Faculty Sponsor

Dr. Todd Hillwig


Arts and Sciences


Physics and Astronomy

Presentation Type

Poster Presentation

Symposium Date

Summer 7-29-2022


We present the results of modeling the central binary star system within three planetary nebulae: Th 3-15, HaTr 4,and Hf 2-2. Brightness data of each binary star was obtained using a number of different telescopes, reduced, folded into a single orbital period for ease of visualization and analysis, and then imported into our modeling software PHOEBE. The software allows us to manipulate nine physical parameters to create a model of the system. These parameters are the temperatures, masses and radii of each star along with the inclination, secondary albedo and system radial velocity. Here we present the current results of our modeling along with a discussion of the impact of the results on our understanding of these systems. Further fine tuning of our binary models, when combined with spatio-kinematic models of the gaseous nebulae surrounding them, will provide an almost full picture of how these two distinct parts of the larger system are interacting and affecting one another over time. We expect to use these results in the future to further understand the relationship between the prominent shaping of planetary nebulae and the presence of a central binary star system.

Biographical Information about Author(s)

Emily Pavasars is a rising Junior at Valparaiso University with a major in Physics and minors in education and mathematics. She has always been interested in astronomy and began working with planetary nebulae and close binaries last summer. She plans to go to graduate school in the future and to continue doing research.

Lane Scheel is a rising Sophomore at Valparaiso University. Interested at a young age by the means by which the things around him worked, he would eventually ask himself, “How does the universe work?”. This simple question has led to him majoring in Physics and Mathematics, where he has undertaken research of close binary stars among other things. Lane wishes to pursue a PhD in Astrophysics and a lifelong career in research and academia.

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