Faculty Sponsor

Dr. Todd Hillwig

Streaming Media


Arts and Sciences


Physics and Astronomy

Presentation Type

Poster Presentation

Symposium Date

Summer 7-24-2020


The aim of this research was to learn more about close binary star systems and how they influence the formation of planetary nebulae at the end of a star’s life. These systems are produced by a common envelope phase where they share the same atmosphere and spiral closer together, causing stronger interactions between the stars. Properties of these systems can be used to better understand Type 1A supernovae, cataclysmic variable stars, and gravitational waves. There are 70 of these close binary star systems known, of which fewer than 20 have been modeled. This summer, models were generated for two of these systems, the central stars of Lo 16 and PHR 1510-6754. The parameters determined were masses, radii, temperatures, inclination, and separation of the stars. Both systems have an irradiation effect, with Lo 16 displaying a small eclipse. Possible solutions for both systems have been found, and at this time, the models indicate stellar parameters that are consistent with the expected ranges for these systems. Further work will aim for a more complete range of all possible parameters. Knowing the specific combination of parameters will lead to a better understanding of how these systems form, how they impact the shaping of the planetary nebula, and how they will continue to evolve in the future.

Biographical Information about Author(s)

Maggie Bliese is a junior at Valparaiso University, majoring in physics with a minor in math. She worked under Prof. Hillwig summer of 2019 on a different aspect of binary star research involving photometry and image reductions, and has enjoyed the opportunity to build on that work this summer. She plans to continue on to grad school for astrophysics. Laura Floyd is an upcoming sophomore at Valparaiso University. She is studying physics and electrical engineering along with German and secondary education. Her work with Professor Hillwig is her first research project as an undergraduate student, but she has previously worked on identifying pulsars as well. She plans to continue her education at graduate school.