Periodic Variability Studies in Proto-Planetary Nebula and Hypergiant Candidates

Primary Submission Contact

Stephen Freund

Faculty Sponsor

Bruce Hrivnak

Faculty Sponsor Email Address



Arts and Sciences


Physics ad Astonomy

Document Type

Poster Presentation


Fall 10-22-2015


As stars age, they go through stages in their life cycles. After the red giant stage, medium mass stars like the Sun enter the proto-planetary nebula stage on the way to becoming a planetary nebula before turning in to a white dwarf. High mass stars enter the hypergiant stage on the way to exploding in a supernova. We observe about 25 of these stars on clear nights using the VU Observatory. We combine the nightly data for each star into light curves and analyze the curves for periods in brightness variation as well as other relations. These findings are useful for determining the physical properties of the stars as they evolve. My individual project involves studying two hypergiant candidates, IRAS 19114+0002 and IRAS 19244+1115, and one proto-planetary nebula candidate, IRAS 20004+2955. I will present the light curves of these three stars and describe the results of my period analysis of the data. I have found periods ranging from 100 to 300 days. My mentors for the project are Dr. Bruce Hrivnak and Mr. Wenxian Lu. Our work is funded by the National Science Foundation and the Indiana Space Grant Consortium.

Biographical Information about Author(s)

Stephen Freund is a senior physics major interested in pursuing a PhD in stellar astrophysics, specifically studying how stars form and evolve.

Additional Presentation Information

Wall Poster

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